Switch over to Lerna + Yarn Workspaces setup for a mono-repo approach

65 files changed, 10804 insertions, 0 deletions

diff --git a/packages/0x.js/README.md b/packages/0x.js/README.md
new file mode 100644
index 000000000..4b6cc8df4
--- /dev/null
+++ b/packages/0x.js/README.md
@@ -0,0 +1,37 @@
+## Installation
+
+0x.js ships as both a [UMD](https://github.com/umdjs/umd) module and a [CommonJS](https://en.wikipedia.org/wiki/CommonJS) package.
+
+#### CommonJS *(recommended)*:
+
+**Install**
+
+```bash
+npm install 0x.js --save
+```
+
+**Import**
+
+```javascript
+import {ZeroEx} from '0x.js';
+```
+
+#### UMD:
+
+**Install**
+
+Download the UMD module from our [releases page](https://github.com/0xProject/0x.js/releases) and add it to your project.
+
+**Import**
+
+```html
+<script type="text/javascript" src="0x.js"></script>
+```
+
+## Documentation
+
+Extensive documentation of 0x.js can be found on [our website][docs-url].
+
+[website-url]: https://0xproject.com/
+[whitepaper-url]: https://0xproject.com/pdfs/0x_white_paper.pdf
+[docs-url]: https://0xproject.com/docs/0xjs
diff --git a/packages/0x.js/package.json b/packages/0x.js/package.json
new file mode 100644
index 000000000..1d3b0c7d2
--- /dev/null
+++ b/packages/0x.js/package.json
@@ -0,0 +1,106 @@
+{
+  "name": "0x.js",
+  "version": "0.23.0",
+  "description": "A javascript library for interacting with the 0x protocol",
+  "keywords": [
+    "0x.js",
+    "0xproject",
+    "ethereum",
+    "tokens",
+    "exchange"
+  ],
+  "main": "lib/src/index.js",
+  "types": "lib/src/index.d.ts",
+  "scripts": {
+    "prebuild": "npm run clean",
+    "build": "run-p build:umd:prod build:commonjs",
+    "prepublishOnly": "run-p build",
+    "postpublish": "run-s release docs:json upload_docs_json",
+    "release": "publish-release --assets _bundles/index.js,_bundles/index.min.js --tag $(git describe --tags) --owner 0xProject --repo 0x.js",
+    "upload_docs_json": "aws s3 cp docs/index.json s3://0xjs-docs-jsons/$(git describe --tags).json --profile 0xproject --grants read=uri=http://acs.amazonaws.com/groups/global/AllUsers --content-type aplication/json",
+    "lint": "tslint src/**/*.ts test/**/*.ts",
+    "test": "run-s clean test:commonjs",
+    "test:umd": "./scripts/test_umd.sh",
+    "test:coverage": "nyc npm run test --all",
+    "report_test_coverage": "nyc report --reporter=text-lcov | coveralls",
+    "update_contracts": "for i in ${npm_package_config_artifacts}; do copyfiles -u 4 ../contracts/build/contracts/$i.json ../0x.js/src/artifacts; done;",
+    "testrpc": "testrpc -p 8545 --networkId 50 -m \"${npm_package_config_mnemonic}\"",
+    "docs:json": "typedoc --excludePrivate --excludeExternals --target ES5 --json docs/index.json .",
+    "docs:generate": "typedoc --out docs .",
+    "docs:open": "opn docs/index.html",
+    "clean": "shx rm -rf _bundles lib test_temp",
+    "build:umd:dev": "webpack",
+    "build:umd:prod": "NODE_ENV=production webpack",
+    "build:commonjs": "tsc; copyfiles -u 2 './src/artifacts/**/*.json' ./lib/src/artifacts;",
+    "test:commonjs": "run-s build:commonjs run_mocha",
+    "pretest:umd": "run-s clean build:umd:dev build:commonjs",
+    "substitute_umd_bundle": "npm run remove_src_files_not_used_by_tests; shx mv _bundles/* lib/src",
+    "remove_src_files_not_used_by_tests": "find ./lib/src \\( -path ./lib/src/utils -o -path ./lib/src/subproviders -o -path ./lib/src/schemas -o -path \"./lib/src/types.*\" \\) -prune -o -type f -print | xargs rm",
+    "run_mocha": "mocha lib/test/**/*_test.js --timeout 5000 --bail --exit"
+  },
+  "config": {
+    "artifacts": "TokenTransferProxy Exchange TokenRegistry Token EtherToken",
+    "mnemonic": "concert load couple harbor equip island argue ramp clarify fence smart topic"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/0xProject/0x.js"
+  },
+  "license": "Apache-2.0",
+  "engines": {
+    "node": ">=6.0.0"
+  },
+  "devDependencies": {
+    "@types/jsonschema": "^1.1.1",
+    "@types/lodash": "^4.14.64",
+    "@types/mocha": "^2.2.41",
+    "@types/node": "^8.0.1",
+    "@types/sinon": "^2.2.2",
+    "@types/uuid": "^3.4.2",
+    "awesome-typescript-loader": "^3.1.3",
+    "chai": "^4.0.1",
+    "chai-as-promised": "^7.1.0",
+    "chai-as-promised-typescript-typings": "0.0.3",
+    "chai-bignumber": "^2.0.1",
+    "chai-typescript-typings": "^0.0.1",
+    "copyfiles": "^1.2.0",
+    "coveralls": "^3.0.0",
+    "dirty-chai": "^2.0.1",
+    "ethereumjs-testrpc": "4.0.1",
+    "json-loader": "^0.5.4",
+    "mocha": "^4.0.0",
+    "npm-run-all": "^4.0.2",
+    "nyc": "^11.0.1",
+    "opn-cli": "^3.1.0",
+    "request": "^2.81.0",
+    "request-promise-native": "^1.0.4",
+    "shx": "^0.2.2",
+    "sinon": "^4.0.0",
+    "source-map-support": "^0.5.0",
+    "truffle-hdwallet-provider": "^0.0.3",
+    "tslint": "~5.5.0",
+    "tslint-config-0xproject": "^0.0.2",
+    "typedoc": "~0.8.0",
+    "types-bn": "^0.0.1",
+    "types-ethereumjs-util": "0xProject/types-ethereumjs-util",
+    "typescript": "^2.4.1",
+    "web3-provider-engine": "^13.0.1",
+    "web3-typescript-typings": "^0.7.1",
+    "webpack": "^3.1.0"
+  },
+  "dependencies": {
+    "0x-json-schemas": "^0.6.1",
+    "bignumber.js": "^4.1.0",
+    "compare-versions": "^3.0.1",
+    "es6-promisify": "^5.0.0",
+    "ethereumjs-abi": "^0.6.4",
+    "ethereumjs-blockstream": "^2.0.6",
+    "ethereumjs-util": "^5.1.1",
+    "find-versions": "^2.0.0",
+    "js-sha3": "^0.6.1",
+    "lodash": "^4.17.4",
+    "publish-release": "^1.3.3",
+    "uuid": "^3.1.0",
+    "web3": "^0.20.0"
+  }
+}
diff --git a/packages/0x.js/scripts/test_umd.sh b/packages/0x.js/scripts/test_umd.sh
new file mode 100755
index 000000000..d200c76d0
--- /dev/null
+++ b/packages/0x.js/scripts/test_umd.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+# This script runs umd tests and cleans up after them while preserving the `return_code` for CI
+# UMD tests should only be run after building the commonjs because they reuse some of the commonjs build artifacts
+run-s substitute_umd_bundle run_mocha
+return_code=$?
+npm run clean
+exit $return_code
diff --git a/packages/0x.js/src/0x.ts b/packages/0x.js/src/0x.ts
new file mode 100644
index 000000000..fe765bbbe
--- /dev/null
+++ b/packages/0x.js/src/0x.ts
@@ -0,0 +1,333 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {SchemaValidator, schemas} from '0x-json-schemas';
+import {bigNumberConfigs} from './bignumber_config';
+import * as ethUtil from 'ethereumjs-util';
+import {Web3Wrapper} from './web3_wrapper';
+import {constants} from './utils/constants';
+import {utils} from './utils/utils';
+import {signatureUtils} from './utils/signature_utils';
+import {assert} from './utils/assert';
+import {AbiDecoder} from './utils/abi_decoder';
+import {intervalUtils} from './utils/interval_utils';
+import {artifacts} from './artifacts';
+import {ExchangeWrapper} from './contract_wrappers/exchange_wrapper';
+import {TokenRegistryWrapper} from './contract_wrappers/token_registry_wrapper';
+import {EtherTokenWrapper} from './contract_wrappers/ether_token_wrapper';
+import {TokenWrapper} from './contract_wrappers/token_wrapper';
+import {TokenTransferProxyWrapper} from './contract_wrappers/token_transfer_proxy_wrapper';
+import {OrderStateWatcher} from './order_watcher/order_state_watcher';
+import {OrderStateUtils} from './utils/order_state_utils';
+import {
+    ECSignature,
+    ZeroExError,
+    Order,
+    SignedOrder,
+    Web3Provider,
+    ZeroExConfig,
+    OrderStateWatcherConfig,
+    TransactionReceiptWithDecodedLogs,
+} from './types';
+import {zeroExConfigSchema} from './schemas/zero_ex_config_schema';
+
+// Customize our BigNumber instances
+bigNumberConfigs.configure();
+
+/**
+ * The ZeroEx class is the single entry-point into the 0x.js library. It contains all of the library's functionality
+ * and all calls to the library should be made through a ZeroEx instance.
+ */
+export class ZeroEx {
+    /**
+     * When creating an order without a specified taker or feeRecipient you must supply the Solidity
+     * address null type (as opposed to Javascripts `null`, `undefined` or empty string). We expose
+     * this constant for your convenience.
+     */
+    public static NULL_ADDRESS = constants.NULL_ADDRESS;
+
+    /**
+     * An instance of the ExchangeWrapper class containing methods for interacting with the 0x Exchange smart contract.
+     */
+    public exchange: ExchangeWrapper;
+    /**
+     * An instance of the TokenRegistryWrapper class containing methods for interacting with the 0x
+     * TokenRegistry smart contract.
+     */
+    public tokenRegistry: TokenRegistryWrapper;
+    /**
+     * An instance of the TokenWrapper class containing methods for interacting with any ERC20 token smart contract.
+     */
+    public token: TokenWrapper;
+    /**
+     * An instance of the EtherTokenWrapper class containing methods for interacting with the
+     * wrapped ETH ERC20 token smart contract.
+     */
+    public etherToken: EtherTokenWrapper;
+    /**
+     * An instance of the TokenTransferProxyWrapper class containing methods for interacting with the
+     * tokenTransferProxy smart contract.
+     */
+    public proxy: TokenTransferProxyWrapper;
+    /**
+     * An instance of the OrderStateWatcher class containing methods for watching a set of orders for relevant
+     * blockchain state changes.
+     */
+    public orderStateWatcher: OrderStateWatcher;
+    private _web3Wrapper: Web3Wrapper;
+    private _abiDecoder: AbiDecoder;
+    /**
+     * Verifies that the elliptic curve signature `signature` was generated
+     * by signing `data` with the private key corresponding to the `signerAddress` address.
+     * @param   data          The hex encoded data signed by the supplied signature.
+     * @param   signature     An object containing the elliptic curve signature parameters.
+     * @param   signerAddress The hex encoded address that signed the data, producing the supplied signature.
+     * @return  Whether the signature is valid for the supplied signerAddress and data.
+     */
+    public static isValidSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
+        assert.isHexString('data', data);
+        assert.doesConformToSchema('signature', signature, schemas.ecSignatureSchema);
+        assert.isETHAddressHex('signerAddress', signerAddress);
+
+        const isValidSignature = signatureUtils.isValidSignature(data, signature, signerAddress);
+        return isValidSignature;
+    }
+    /**
+     * Generates a pseudo-random 256-bit salt.
+     * The salt can be included in an 0x order, ensuring that the order generates a unique orderHash
+     * and will not collide with other outstanding orders that are identical in all other parameters.
+     * @return  A pseudo-random 256-bit number that can be used as a salt.
+     */
+    public static generatePseudoRandomSalt(): BigNumber {
+        // BigNumber.random returns a pseudo-random number between 0 & 1 with a passed in number of decimal places.
+        // Source: https://mikemcl.github.io/bignumber.js/#random
+        const randomNumber = BigNumber.random(constants.MAX_DIGITS_IN_UNSIGNED_256_INT);
+        const factor = new BigNumber(10).pow(constants.MAX_DIGITS_IN_UNSIGNED_256_INT - 1);
+        const salt = randomNumber.times(factor).round();
+        return salt;
+    }
+    /**
+     * Checks if the supplied hex encoded order hash is valid.
+     * Note: Valid means it has the expected format, not that an order with the orderHash exists.
+     * Use this method when processing orderHashes submitted as user input.
+     * @param   orderHash    Hex encoded orderHash.
+     * @return  Whether the supplied orderHash has the expected format.
+     */
+    public static isValidOrderHash(orderHash: string): boolean {
+        // Since this method can be called to check if any arbitrary string conforms to an orderHash's
+        // format, we only assert that we were indeed passed a string.
+        assert.isString('orderHash', orderHash);
+        const schemaValidator = new SchemaValidator();
+        const isValidOrderHash = schemaValidator.validate(orderHash, schemas.orderHashSchema).valid;
+        return isValidOrderHash;
+    }
+    /**
+     * A unit amount is defined as the amount of a token above the specified decimal places (integer part).
+     * E.g: If a currency has 18 decimal places, 1e18 or one quintillion of the currency is equivalent
+     * to 1 unit.
+     * @param   amount      The amount in baseUnits that you would like converted to units.
+     * @param   decimals    The number of decimal places the unit amount has.
+     * @return  The amount in units.
+     */
+    public static toUnitAmount(amount: BigNumber, decimals: number): BigNumber {
+        assert.isBigNumber('amount', amount);
+        assert.isNumber('decimals', decimals);
+
+        const aUnit = new BigNumber(10).pow(decimals);
+        const unit = amount.div(aUnit);
+        return unit;
+    }
+    /**
+     * A baseUnit is defined as the smallest denomination of a token. An amount expressed in baseUnits
+     * is the amount expressed in the smallest denomination.
+     * E.g: 1 unit of a token with 18 decimal places is expressed in baseUnits as 1000000000000000000
+     * @param   amount      The amount of units that you would like converted to baseUnits.
+     * @param   decimals    The number of decimal places the unit amount has.
+     * @return  The amount in baseUnits.
+     */
+    public static toBaseUnitAmount(amount: BigNumber, decimals: number): BigNumber {
+        assert.isBigNumber('amount', amount);
+        assert.isNumber('decimals', decimals);
+
+        const unit = new BigNumber(10).pow(decimals);
+        const baseUnitAmount = amount.times(unit);
+        return baseUnitAmount;
+    }
+    /**
+     * Computes the orderHash for a supplied order.
+     * @param   order   An object that conforms to the Order or SignedOrder interface definitions.
+     * @return  The resulting orderHash from hashing the supplied order.
+     */
+    public static getOrderHashHex(order: Order|SignedOrder): string {
+        assert.doesConformToSchema('order', order, schemas.orderSchema);
+        const orderHashHex = utils.getOrderHashHex(order);
+        return orderHashHex;
+    }
+    /**
+     * Instantiates a new ZeroEx instance that provides the public interface to the 0x.js library.
+     * @param   provider    The Web3.js Provider instance you would like the 0x.js library to use for interacting with
+     *                      the Ethereum network.
+     * @param   config      The configuration object. Look up the type for the description.
+     * @return  An instance of the 0x.js ZeroEx class.
+     */
+    constructor(provider: Web3Provider, config?: ZeroExConfig) {
+        assert.isWeb3Provider('provider', provider);
+        if (!_.isUndefined(config)) {
+            assert.doesConformToSchema('config', config, zeroExConfigSchema);
+        }
+        const artifactJSONs = _.values(artifacts);
+        const abiArrays = _.map(artifactJSONs, artifact => artifact.abi);
+        this._abiDecoder = new AbiDecoder(abiArrays);
+        const gasPrice = _.isUndefined(config) ? undefined : config.gasPrice;
+        const defaults = {
+            gasPrice,
+        };
+        this._web3Wrapper = new Web3Wrapper(provider, defaults);
+        this.token = new TokenWrapper(
+            this._web3Wrapper,
+            this._abiDecoder,
+            this._getTokenTransferProxyAddressAsync.bind(this),
+        );
+        const exchageContractAddressIfExists = _.isUndefined(config) ? undefined : config.exchangeContractAddress;
+        this.exchange = new ExchangeWrapper(
+            this._web3Wrapper,
+            this._abiDecoder,
+            this.token,
+            exchageContractAddressIfExists,
+        );
+        this.proxy = new TokenTransferProxyWrapper(
+            this._web3Wrapper,
+            this._getTokenTransferProxyAddressAsync.bind(this),
+        );
+        const tokenRegistryContractAddressIfExists = _.isUndefined(config) ?
+                                                     undefined :
+                                                     config.tokenRegistryContractAddress;
+        this.tokenRegistry = new TokenRegistryWrapper(this._web3Wrapper, tokenRegistryContractAddressIfExists);
+        const etherTokenContractAddressIfExists = _.isUndefined(config) ? undefined : config.etherTokenContractAddress;
+        this.etherToken = new EtherTokenWrapper(this._web3Wrapper, this.token, etherTokenContractAddressIfExists);
+        const orderWatcherConfig = _.isUndefined(config) ? undefined : config.orderWatcherConfig;
+        this.orderStateWatcher = new OrderStateWatcher(
+            this._web3Wrapper, this._abiDecoder, this.token, this.exchange, orderWatcherConfig,
+        );
+    }
+    /**
+     * Sets a new web3 provider for 0x.js. Updating the provider will stop all
+     * subscriptions so you will need to re-subscribe to all events relevant to your app after this call.
+     * @param   provider    The Web3Provider you would like the 0x.js library to use from now on.
+     */
+    public async setProviderAsync(provider: Web3Provider) {
+        this._web3Wrapper.setProvider(provider);
+        await (this.exchange as any)._invalidateContractInstancesAsync();
+        (this.tokenRegistry as any)._invalidateContractInstance();
+        await (this.token as any)._invalidateContractInstancesAsync();
+        (this.proxy as any)._invalidateContractInstance();
+        (this.etherToken as any)._invalidateContractInstance();
+    }
+    /**
+     * Get user Ethereum addresses available through the supplied web3 provider available for sending transactions.
+     * @return  An array of available user Ethereum addresses.
+     */
+    public async getAvailableAddressesAsync(): Promise<string[]> {
+        const availableAddresses = await this._web3Wrapper.getAvailableAddressesAsync();
+        return availableAddresses;
+    }
+    /**
+     * Signs an orderHash and returns it's elliptic curve signature.
+     * This method currently supports TestRPC, Geth and Parity above and below V1.6.6
+     * @param   orderHash       Hex encoded orderHash to sign.
+     * @param   signerAddress   The hex encoded Ethereum address you wish to sign it with. This address
+     *          must be available via the Web3.Provider supplied to 0x.js.
+     * @return  An object containing the Elliptic curve signature parameters generated by signing the orderHash.
+     */
+    public async signOrderHashAsync(orderHash: string, signerAddress: string): Promise<ECSignature> {
+        assert.isHexString('orderHash', orderHash);
+        await assert.isSenderAddressAsync('signerAddress', signerAddress, this._web3Wrapper);
+
+        let msgHashHex;
+        const nodeVersion = await this._web3Wrapper.getNodeVersionAsync();
+        const isParityNode = utils.isParityNode(nodeVersion);
+        const isTestRpc = utils.isTestRpc(nodeVersion);
+        if (isParityNode || isTestRpc) {
+            // Parity and TestRpc nodes add the personalMessage prefix itself
+            msgHashHex = orderHash;
+        } else {
+            const orderHashBuff = ethUtil.toBuffer(orderHash);
+            const msgHashBuff = ethUtil.hashPersonalMessage(orderHashBuff);
+            msgHashHex = ethUtil.bufferToHex(msgHashBuff);
+        }
+
+        const signature = await this._web3Wrapper.signTransactionAsync(signerAddress, msgHashHex);
+
+        // HACK: There is no consensus on whether the signatureHex string should be formatted as
+        // v + r + s OR r + s + v, and different clients (even different versions of the same client)
+        // return the signature params in different orders. In order to support all client implementations,
+        // we parse the signature in both ways, and evaluate if either one is a valid signature.
+        const validVParamValues = [27, 28];
+        const ecSignatureVRS = signatureUtils.parseSignatureHexAsVRS(signature);
+        if (_.includes(validVParamValues, ecSignatureVRS.v)) {
+            const isValidVRSSignature = ZeroEx.isValidSignature(orderHash, ecSignatureVRS, signerAddress);
+            if (isValidVRSSignature) {
+                return ecSignatureVRS;
+            }
+        }
+
+        const ecSignatureRSV = signatureUtils.parseSignatureHexAsRSV(signature);
+        if (_.includes(validVParamValues, ecSignatureRSV.v)) {
+            const isValidRSVSignature = ZeroEx.isValidSignature(orderHash, ecSignatureRSV, signerAddress);
+            if (isValidRSVSignature) {
+                return ecSignatureRSV;
+            }
+        }
+
+        throw new Error(ZeroExError.InvalidSignature);
+    }
+    /**
+     * Waits for a transaction to be mined and returns the transaction receipt.
+     * @param   txHash            Transaction hash
+     * @param   pollingIntervalMs How often (in ms) should we check if the transaction is mined.
+     * @param   timeoutMs         How long (in ms) to poll for transaction mined until aborting.
+     * @return  Transaction receipt with decoded log args.
+     */
+    public async awaitTransactionMinedAsync(
+        txHash: string, pollingIntervalMs = 1000, timeoutMs?: number): Promise<TransactionReceiptWithDecodedLogs> {
+        let timeoutExceeded = false;
+        if (timeoutMs) {
+            setTimeout(() => timeoutExceeded = true, timeoutMs);
+        }
+
+        const txReceiptPromise = new Promise(
+            (resolve: (receipt: TransactionReceiptWithDecodedLogs) => void, reject) => {
+            const intervalId = intervalUtils.setAsyncExcludingInterval(async () => {
+                if (timeoutExceeded) {
+                    intervalUtils.clearAsyncExcludingInterval(intervalId);
+                    return reject(ZeroExError.TransactionMiningTimeout);
+                }
+
+                const transactionReceipt = await this._web3Wrapper.getTransactionReceiptAsync(txHash);
+                if (!_.isNull(transactionReceipt)) {
+                    intervalUtils.clearAsyncExcludingInterval(intervalId);
+                    const logsWithDecodedArgs = _.map(
+                        transactionReceipt.logs,
+                        this._abiDecoder.tryToDecodeLogOrNoop.bind(this._abiDecoder),
+                    );
+                    const transactionReceiptWithDecodedLogArgs: TransactionReceiptWithDecodedLogs = {
+                        ...transactionReceipt,
+                        logs: logsWithDecodedArgs,
+                    };
+                    resolve(transactionReceiptWithDecodedLogArgs);
+                }
+            }, pollingIntervalMs);
+        });
+
+        return txReceiptPromise;
+    }
+    /*
+     * HACK: `TokenWrapper` needs a token transfer proxy address. `TokenTransferProxy` address is fetched from
+     * an `ExchangeWrapper`. `ExchangeWrapper` needs `TokenWrapper` to validate orders, creating a dependency cycle.
+     * In order to break this - we create this function here and pass it as a parameter to the `TokenWrapper`
+     * and `ProxyWrapper`.
+     */
+    private async _getTokenTransferProxyAddressAsync(): Promise<string> {
+        const tokenTransferProxyAddress = await (this.exchange as any)._getTokenTransferProxyAddressAsync();
+        return tokenTransferProxyAddress;
+    }
+}
diff --git a/packages/0x.js/src/artifacts.ts b/packages/0x.js/src/artifacts.ts
new file mode 100644
index 000000000..447f9880a
--- /dev/null
+++ b/packages/0x.js/src/artifacts.ts
@@ -0,0 +1,14 @@
+import {Artifact} from './types';
+import * as TokenArtifact from './artifacts/Token.json';
+import * as ExchangeArtifact from './artifacts/Exchange.json';
+import * as EtherTokenArtifact from './artifacts/EtherToken.json';
+import * as TokenRegistryArtifact from './artifacts/TokenRegistry.json';
+import * as TokenTransferProxyArtifact from './artifacts/TokenTransferProxy.json';
+
+export const artifacts = {
+    TokenArtifact: TokenArtifact as any as Artifact,
+    ExchangeArtifact: ExchangeArtifact as any as Artifact,
+    EtherTokenArtifact: EtherTokenArtifact as any as Artifact,
+    TokenRegistryArtifact: TokenRegistryArtifact as any as Artifact,
+    TokenTransferProxyArtifact: TokenTransferProxyArtifact as any as Artifact,
+};
diff --git a/packages/0x.js/src/artifacts/EtherToken.json b/packages/0x.js/src/artifacts/EtherToken.json
new file mode 100644
index 000000000..91b23bc94
--- /dev/null
+++ b/packages/0x.js/src/artifacts/EtherToken.json
@@ -0,0 +1,445 @@
+{
+  "contract_name": "EtherToken",
+  "abi": [
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "name",
+      "outputs": [
+        {
+          "name": "",
+          "type": "string"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_spender",
+          "type": "address"
+        },
+        {
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "approve",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "totalSupply",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_from",
+          "type": "address"
+        },
+        {
+          "name": "_to",
+          "type": "address"
+        },
+        {
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "transferFrom",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "amount",
+          "type": "uint256"
+        }
+      ],
+      "name": "withdraw",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "decimals",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint8"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_owner",
+          "type": "address"
+        }
+      ],
+      "name": "balanceOf",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "symbol",
+      "outputs": [
+        {
+          "name": "",
+          "type": "string"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_to",
+          "type": "address"
+        },
+        {
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "transfer",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [],
+      "name": "deposit",
+      "outputs": [],
+      "payable": true,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_owner",
+          "type": "address"
+        },
+        {
+          "name": "_spender",
+          "type": "address"
+        }
+      ],
+      "name": "allowance",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "payable": true,
+      "type": "fallback"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "_from",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "_to",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "Transfer",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "_owner",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "_spender",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "Approval",
+      "type": "event"
+    }
+  ],
+  "unlinked_binary": "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",
+  "networks": {
+    "1": {
+      "links": {},
+      "events": {
+        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_from",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_to",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Transfer",
+          "type": "event"
+        },
+        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_owner",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_spender",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Approval",
+          "type": "event"
+        }
+      },
+      "updated_at": 1502488087000,
+      "address": "0x2956356cd2a2bf3202f771f50d3d14a367b48070"
+    },
+    "3": {
+      "links": {},
+      "events": {
+        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_from",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_to",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Transfer",
+          "type": "event"
+        },
+        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_owner",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_spender",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Approval",
+          "type": "event"
+        }
+      },
+      "updated_at": 1506602007000,
+      "address": "0xc00fd9820cd2898cc4c054b7bf142de637ad129a"
+    },
+    "42": {
+      "links": {},
+      "events": {
+        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_from",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_to",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Transfer",
+          "type": "event"
+        },
+        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_owner",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_spender",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Approval",
+          "type": "event"
+        }
+      },
+      "updated_at": 1502391794392,
+      "address": "0x05d090b51c40b020eab3bfcb6a2dff130df22e9c"
+    },
+    "50": {
+      "links": {},
+      "events": {
+        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_from",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_to",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Transfer",
+          "type": "event"
+        },
+        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "_owner",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "_spender",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "_value",
+              "type": "uint256"
+            }
+          ],
+          "name": "Approval",
+          "type": "event"
+        }
+      },
+      "updated_at": 1503318938233,
+      "address": "0x48bacb9266a570d521063ef5dd96e61686dbe788"
+    }
+  },
+  "schema_version": "0.0.5",
+  "updated_at": 1503318938233
+}
diff --git a/packages/0x.js/src/artifacts/Exchange.json b/packages/0x.js/src/artifacts/Exchange.json
new file mode 100644
index 000000000..734c8f9c7
--- /dev/null
+++ b/packages/0x.js/src/artifacts/Exchange.json
@@ -0,0 +1,1130 @@
+{
+  "contract_name": "Exchange",
+  "abi": [
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "numerator",
+          "type": "uint256"
+        },
+        {
+          "name": "denominator",
+          "type": "uint256"
+        },
+        {
+          "name": "target",
+          "type": "uint256"
+        }
+      ],
+      "name": "isRoundingError",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "",
+          "type": "bytes32"
+        }
+      ],
+      "name": "filled",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "",
+          "type": "bytes32"
+        }
+      ],
+      "name": "cancelled",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5][]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6][]"
+        },
+        {
+          "name": "fillTakerTokenAmount",
+          "type": "uint256"
+        },
+        {
+          "name": "shouldThrowOnInsufficientBalanceOrAllowance",
+          "type": "bool"
+        },
+        {
+          "name": "v",
+          "type": "uint8[]"
+        },
+        {
+          "name": "r",
+          "type": "bytes32[]"
+        },
+        {
+          "name": "s",
+          "type": "bytes32[]"
+        }
+      ],
+      "name": "fillOrdersUpTo",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6]"
+        },
+        {
+          "name": "cancelTakerTokenAmount",
+          "type": "uint256"
+        }
+      ],
+      "name": "cancelOrder",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "ZRX_TOKEN_CONTRACT",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5][]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6][]"
+        },
+        {
+          "name": "fillTakerTokenAmounts",
+          "type": "uint256[]"
+        },
+        {
+          "name": "v",
+          "type": "uint8[]"
+        },
+        {
+          "name": "r",
+          "type": "bytes32[]"
+        },
+        {
+          "name": "s",
+          "type": "bytes32[]"
+        }
+      ],
+      "name": "batchFillOrKillOrders",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6]"
+        },
+        {
+          "name": "fillTakerTokenAmount",
+          "type": "uint256"
+        },
+        {
+          "name": "v",
+          "type": "uint8"
+        },
+        {
+          "name": "r",
+          "type": "bytes32"
+        },
+        {
+          "name": "s",
+          "type": "bytes32"
+        }
+      ],
+      "name": "fillOrKillOrder",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "orderHash",
+          "type": "bytes32"
+        }
+      ],
+      "name": "getUnavailableTakerTokenAmount",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "signer",
+          "type": "address"
+        },
+        {
+          "name": "hash",
+          "type": "bytes32"
+        },
+        {
+          "name": "v",
+          "type": "uint8"
+        },
+        {
+          "name": "r",
+          "type": "bytes32"
+        },
+        {
+          "name": "s",
+          "type": "bytes32"
+        }
+      ],
+      "name": "isValidSignature",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "numerator",
+          "type": "uint256"
+        },
+        {
+          "name": "denominator",
+          "type": "uint256"
+        },
+        {
+          "name": "target",
+          "type": "uint256"
+        }
+      ],
+      "name": "getPartialAmount",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "TOKEN_TRANSFER_PROXY_CONTRACT",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5][]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6][]"
+        },
+        {
+          "name": "fillTakerTokenAmounts",
+          "type": "uint256[]"
+        },
+        {
+          "name": "shouldThrowOnInsufficientBalanceOrAllowance",
+          "type": "bool"
+        },
+        {
+          "name": "v",
+          "type": "uint8[]"
+        },
+        {
+          "name": "r",
+          "type": "bytes32[]"
+        },
+        {
+          "name": "s",
+          "type": "bytes32[]"
+        }
+      ],
+      "name": "batchFillOrders",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5][]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6][]"
+        },
+        {
+          "name": "cancelTakerTokenAmounts",
+          "type": "uint256[]"
+        }
+      ],
+      "name": "batchCancelOrders",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6]"
+        },
+        {
+          "name": "fillTakerTokenAmount",
+          "type": "uint256"
+        },
+        {
+          "name": "shouldThrowOnInsufficientBalanceOrAllowance",
+          "type": "bool"
+        },
+        {
+          "name": "v",
+          "type": "uint8"
+        },
+        {
+          "name": "r",
+          "type": "bytes32"
+        },
+        {
+          "name": "s",
+          "type": "bytes32"
+        }
+      ],
+      "name": "fillOrder",
+      "outputs": [
+        {
+          "name": "filledTakerTokenAmount",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "orderAddresses",
+          "type": "address[5]"
+        },
+        {
+          "name": "orderValues",
+          "type": "uint256[6]"
+        }
+      ],
+      "name": "getOrderHash",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bytes32"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "EXTERNAL_QUERY_GAS_LIMIT",
+      "outputs": [
+        {
+          "name": "",
+          "type": "uint16"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "VERSION",
+      "outputs": [
+        {
+          "name": "",
+          "type": "string"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "inputs": [
+        {
+          "name": "_zrxToken",
+          "type": "address"
+        },
+        {
+          "name": "_tokenTransferProxy",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "constructor"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "maker",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "taker",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "feeRecipient",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "makerToken",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "takerToken",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "filledMakerTokenAmount",
+          "type": "uint256"
+        },
+        {
+          "indexed": false,
+          "name": "filledTakerTokenAmount",
+          "type": "uint256"
+        },
+        {
+          "indexed": false,
+          "name": "paidMakerFee",
+          "type": "uint256"
+        },
+        {
+          "indexed": false,
+          "name": "paidTakerFee",
+          "type": "uint256"
+        },
+        {
+          "indexed": true,
+          "name": "tokens",
+          "type": "bytes32"
+        },
+        {
+          "indexed": false,
+          "name": "orderHash",
+          "type": "bytes32"
+        }
+      ],
+      "name": "LogFill",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "maker",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "feeRecipient",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "makerToken",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "takerToken",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "cancelledMakerTokenAmount",
+          "type": "uint256"
+        },
+        {
+          "indexed": false,
+          "name": "cancelledTakerTokenAmount",
+          "type": "uint256"
+        },
+        {
+          "indexed": true,
+          "name": "tokens",
+          "type": "bytes32"
+        },
+        {
+          "indexed": false,
+          "name": "orderHash",
+          "type": "bytes32"
+        }
+      ],
+      "name": "LogCancel",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "errorId",
+          "type": "uint8"
+        },
+        {
+          "indexed": true,
+          "name": "orderHash",
+          "type": "bytes32"
+        }
+      ],
+      "name": "LogError",
+      "type": "event"
+    }
+  ],
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+            },
+            {
+              "indexed": false,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogCancel",
+          "type": "event"
+        },
+        "0x36d86c59e00bd73dc19ba3adfe068e4b64ac7e92be35546adeddf1b956a87e90": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "errorId",
+              "type": "uint8"
+            },
+            {
+              "indexed": true,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogError",
+          "type": "event"
+        }
+      },
+      "updated_at": 1502480340000,
+      "address": "0x12459c951127e0c374ff9105dda097662a027093"
+    },
+    "3": {
+      "links": {},
+      "events": {
+        "0x0d0b9391970d9a25552f37d436d2aae2925e2bfe1b2a923754bada030c498cb3": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "maker",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "taker",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "feeRecipient",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "makerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "takerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "filledMakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "filledTakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "paidMakerFee",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "paidTakerFee",
+              "type": "uint256"
+            },
+            {
+              "indexed": true,
+              "name": "tokens",
+              "type": "bytes32"
+            },
+            {
+              "indexed": false,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogFill",
+          "type": "event"
+        },
+        "0x67d66f160bc93d925d05dae1794c90d2d6d6688b29b84ff069398a9b04587131": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "maker",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "feeRecipient",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "makerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "takerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "cancelledMakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "cancelledTakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": true,
+              "name": "tokens",
+              "type": "bytes32"
+            },
+            {
+              "indexed": false,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogCancel",
+          "type": "event"
+        },
+        "0x36d86c59e00bd73dc19ba3adfe068e4b64ac7e92be35546adeddf1b956a87e90": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "errorId",
+              "type": "uint8"
+            },
+            {
+              "indexed": true,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogError",
+          "type": "event"
+        }
+      },
+      "updated_at": 1506602007000,
+      "address": "0x479cc461fecd078f766ecc58533d6f69580cf3ac"
+    },
+    "42": {
+      "links": {},
+      "events": {
+        "0x0d0b9391970d9a25552f37d436d2aae2925e2bfe1b2a923754bada030c498cb3": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "maker",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "taker",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "feeRecipient",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "makerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "takerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "filledMakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "filledTakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "paidMakerFee",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "paidTakerFee",
+              "type": "uint256"
+            },
+            {
+              "indexed": true,
+              "name": "tokens",
+              "type": "bytes32"
+            },
+            {
+              "indexed": false,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogFill",
+          "type": "event"
+        },
+        "0x67d66f160bc93d925d05dae1794c90d2d6d6688b29b84ff069398a9b04587131": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "maker",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "feeRecipient",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "makerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "takerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "cancelledMakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "cancelledTakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": true,
+              "name": "tokens",
+              "type": "bytes32"
+            },
+            {
+              "indexed": false,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogCancel",
+          "type": "event"
+        },
+        "0x36d86c59e00bd73dc19ba3adfe068e4b64ac7e92be35546adeddf1b956a87e90": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "errorId",
+              "type": "uint8"
+            },
+            {
+              "indexed": true,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogError",
+          "type": "event"
+        }
+      },
+      "updated_at": 1502391794390,
+      "address": "0x90fe2af704b34e0224bf2299c838e04d4dcf1364"
+    },
+    "50": {
+      "links": {},
+      "events": {
+        "0x0d0b9391970d9a25552f37d436d2aae2925e2bfe1b2a923754bada030c498cb3": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "maker",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "taker",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "feeRecipient",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "makerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "takerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "filledMakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "filledTakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "paidMakerFee",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "paidTakerFee",
+              "type": "uint256"
+            },
+            {
+              "indexed": true,
+              "name": "tokens",
+              "type": "bytes32"
+            },
+            {
+              "indexed": false,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogFill",
+          "type": "event"
+        },
+        "0x67d66f160bc93d925d05dae1794c90d2d6d6688b29b84ff069398a9b04587131": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "maker",
+              "type": "address"
+            },
+            {
+              "indexed": true,
+              "name": "feeRecipient",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "makerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "takerToken",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "cancelledMakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": false,
+              "name": "cancelledTakerTokenAmount",
+              "type": "uint256"
+            },
+            {
+              "indexed": true,
+              "name": "tokens",
+              "type": "bytes32"
+            },
+            {
+              "indexed": false,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogCancel",
+          "type": "event"
+        },
+        "0x36d86c59e00bd73dc19ba3adfe068e4b64ac7e92be35546adeddf1b956a87e90": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "errorId",
+              "type": "uint8"
+            },
+            {
+              "indexed": true,
+              "name": "orderHash",
+              "type": "bytes32"
+            }
+          ],
+          "name": "LogError",
+          "type": "event"
+        }
+      },
+      "updated_at": 1503318938231,
+      "address": "0xb69e673309512a9d726f87304c6984054f87a93b"
+    }
+  },
+  "schema_version": "0.0.5",
+  "updated_at": 1503318938231
+}
diff --git a/packages/0x.js/src/artifacts/Token.json b/packages/0x.js/src/artifacts/Token.json
new file mode 100644
index 000000000..e922ff66d
--- /dev/null
+++ b/packages/0x.js/src/artifacts/Token.json
@@ -0,0 +1,176 @@
+{
+  "contract_name": "Token",
+  "abi": [
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_spender",
+          "type": "address"
+        },
+        {
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "approve",
+      "outputs": [
+        {
+          "name": "success",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "totalSupply",
+      "outputs": [
+        {
+          "name": "supply",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_from",
+          "type": "address"
+        },
+        {
+          "name": "_to",
+          "type": "address"
+        },
+        {
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "transferFrom",
+      "outputs": [
+        {
+          "name": "success",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_owner",
+          "type": "address"
+        }
+      ],
+      "name": "balanceOf",
+      "outputs": [
+        {
+          "name": "balance",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_to",
+          "type": "address"
+        },
+        {
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "transfer",
+      "outputs": [
+        {
+          "name": "success",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_owner",
+          "type": "address"
+        },
+        {
+          "name": "_spender",
+          "type": "address"
+        }
+      ],
+      "name": "allowance",
+      "outputs": [
+        {
+          "name": "remaining",
+          "type": "uint256"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "_from",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "_to",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "Transfer",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "_owner",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "_spender",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "Approval",
+      "type": "event"
+    }
+  ],
+  "unlinked_binary": "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",
+  "networks": {},
+  "schema_version": "0.0.5",
+  "updated_at": 1503317882695
+}
\ No newline at end of file
diff --git a/packages/0x.js/src/artifacts/TokenRegistry.json b/packages/0x.js/src/artifacts/TokenRegistry.json
new file mode 100644
index 000000000..5a0564a69
--- /dev/null
+++ b/packages/0x.js/src/artifacts/TokenRegistry.json
@@ -0,0 +1,1211 @@
+{
+  "contract_name": "TokenRegistry",
+  "abi": [
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_token",
+          "type": "address"
+        },
+        {
+          "name": "_index",
+          "type": "uint256"
+        }
+      ],
+      "name": "removeToken",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_name",
+          "type": "string"
+        }
+      ],
+      "name": "getTokenAddressByName",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_symbol",
+          "type": "string"
+        }
+      ],
+      "name": "getTokenAddressBySymbol",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_token",
+          "type": "address"
+        },
+        {
+          "name": "_swarmHash",
+          "type": "bytes"
+        }
+      ],
+      "name": "setTokenSwarmHash",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_token",
+          "type": "address"
+        }
+      ],
+      "name": "getTokenMetaData",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        },
+        {
+          "name": "",
+          "type": "string"
+        },
+        {
+          "name": "",
+          "type": "string"
+        },
+        {
+          "name": "",
+          "type": "uint8"
+        },
+        {
+          "name": "",
+          "type": "bytes"
+        },
+        {
+          "name": "",
+          "type": "bytes"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "owner",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_token",
+          "type": "address"
+        },
+        {
+          "name": "_name",
+          "type": "string"
+        },
+        {
+          "name": "_symbol",
+          "type": "string"
+        },
+        {
+          "name": "_decimals",
+          "type": "uint8"
+        },
+        {
+          "name": "_ipfsHash",
+          "type": "bytes"
+        },
+        {
+          "name": "_swarmHash",
+          "type": "bytes"
+        }
+      ],
+      "name": "addToken",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_token",
+          "type": "address"
+        },
+        {
+          "name": "_name",
+          "type": "string"
+        }
+      ],
+      "name": "setTokenName",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "name": "tokens",
+      "outputs": [
+        {
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "name": "name",
+          "type": "string"
+        },
+        {
+          "name": "symbol",
+          "type": "string"
+        },
+        {
+          "name": "decimals",
+          "type": "uint8"
+        },
+        {
+          "name": "ipfsHash",
+          "type": "bytes"
+        },
+        {
+          "name": "swarmHash",
+          "type": "bytes"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "name": "tokenAddresses",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_name",
+          "type": "string"
+        }
+      ],
+      "name": "getTokenByName",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        },
+        {
+          "name": "",
+          "type": "string"
+        },
+        {
+          "name": "",
+          "type": "string"
+        },
+        {
+          "name": "",
+          "type": "uint8"
+        },
+        {
+          "name": "",
+          "type": "bytes"
+        },
+        {
+          "name": "",
+          "type": "bytes"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "getTokenAddresses",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address[]"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_token",
+          "type": "address"
+        },
+        {
+          "name": "_ipfsHash",
+          "type": "bytes"
+        }
+      ],
+      "name": "setTokenIpfsHash",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "_symbol",
+          "type": "string"
+        }
+      ],
+      "name": "getTokenBySymbol",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        },
+        {
+          "name": "",
+          "type": "string"
+        },
+        {
+          "name": "",
+          "type": "string"
+        },
+        {
+          "name": "",
+          "type": "uint8"
+        },
+        {
+          "name": "",
+          "type": "bytes"
+        },
+        {
+          "name": "",
+          "type": "bytes"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "_token",
+          "type": "address"
+        },
+        {
+          "name": "_symbol",
+          "type": "string"
+        }
+      ],
+      "name": "setTokenSymbol",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "newOwner",
+          "type": "address"
+        }
+      ],
+      "name": "transferOwnership",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "name",
+          "type": "string"
+        },
+        {
+          "indexed": false,
+          "name": "symbol",
+          "type": "string"
+        },
+        {
+          "indexed": false,
+          "name": "decimals",
+          "type": "uint8"
+        },
+        {
+          "indexed": false,
+          "name": "ipfsHash",
+          "type": "bytes"
+        },
+        {
+          "indexed": false,
+          "name": "swarmHash",
+          "type": "bytes"
+        }
+      ],
+      "name": "LogAddToken",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "name",
+          "type": "string"
+        },
+        {
+          "indexed": false,
+          "name": "symbol",
+          "type": "string"
+        },
+        {
+          "indexed": false,
+          "name": "decimals",
+          "type": "uint8"
+        },
+        {
+          "indexed": false,
+          "name": "ipfsHash",
+          "type": "bytes"
+        },
+        {
+          "indexed": false,
+          "name": "swarmHash",
+          "type": "bytes"
+        }
+      ],
+      "name": "LogRemoveToken",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "oldName",
+          "type": "string"
+        },
+        {
+          "indexed": false,
+          "name": "newName",
+          "type": "string"
+        }
+      ],
+      "name": "LogTokenNameChange",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "oldSymbol",
+          "type": "string"
+        },
+        {
+          "indexed": false,
+          "name": "newSymbol",
+          "type": "string"
+        }
+      ],
+      "name": "LogTokenSymbolChange",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "oldIpfsHash",
+          "type": "bytes"
+        },
+        {
+          "indexed": false,
+          "name": "newIpfsHash",
+          "type": "bytes"
+        }
+      ],
+      "name": "LogTokenIpfsHashChange",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "oldSwarmHash",
+          "type": "bytes"
+        },
+        {
+          "indexed": false,
+          "name": "newSwarmHash",
+          "type": "bytes"
+        }
+      ],
+      "name": "LogTokenSwarmHashChange",
+      "type": "event"
+    }
+  ],
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+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogAddToken",
+          "type": "event"
+        },
+        "0x32c54f1e2ea75844ded7517e7dbcd3895da7cd0c28f9ab9f9cf6ecf5f83762c6": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "name",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogRemoveToken",
+          "type": "event"
+        },
+        "0x4a6dbfc867b179991dec22ff19960f0a94d8d9d891fc556f547764670340e8ae": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldName",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newName",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenNameChange",
+          "type": "event"
+        },
+        "0x53d878a6530e56c9bc96548fa0a8cae4f1d1f49c86b0e934c086b992ebb6998f": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSymbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newSymbol",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenSymbolChange",
+          "type": "event"
+        },
+        "0x5b19f79ac4e8cfa820815502e11615f1a449e28155dc289ec5cac1a11f908694": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldIpfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newIpfsHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenIpfsHashChange",
+          "type": "event"
+        },
+        "0xc3168fdc13112e44a031057dbf6c609b33353addb4d8037d24543e22cbfe2acd": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSwarmHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newSwarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenSwarmHashChange",
+          "type": "event"
+        }
+      },
+      "updated_at": 1502488442000,
+      "address": "0x926a74c5c36adf004c87399e65f75628b0f98d2c"
+    },
+    "3": {
+      "links": {},
+      "events": {
+        "0xd8d928b0b50ca11d9dc273236b46f3526515b03602f71f3a6af4f45bd9fa9144": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "name",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogAddToken",
+          "type": "event"
+        },
+        "0x32c54f1e2ea75844ded7517e7dbcd3895da7cd0c28f9ab9f9cf6ecf5f83762c6": {
+          "anonymous": false,
+          "inputs": [
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+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "name",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogRemoveToken",
+          "type": "event"
+        },
+        "0x4a6dbfc867b179991dec22ff19960f0a94d8d9d891fc556f547764670340e8ae": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldName",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newName",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenNameChange",
+          "type": "event"
+        },
+        "0x53d878a6530e56c9bc96548fa0a8cae4f1d1f49c86b0e934c086b992ebb6998f": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSymbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newSymbol",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenSymbolChange",
+          "type": "event"
+        },
+        "0x5b19f79ac4e8cfa820815502e11615f1a449e28155dc289ec5cac1a11f908694": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldIpfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newIpfsHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenIpfsHashChange",
+          "type": "event"
+        },
+        "0xc3168fdc13112e44a031057dbf6c609b33353addb4d8037d24543e22cbfe2acd": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSwarmHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newSwarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenSwarmHashChange",
+          "type": "event"
+        }
+      },
+      "updated_at": 1506602007000,
+      "address": "0x6b1a50f0bb5a7995444bd3877b22dc89c62843ed"
+    },
+    "42": {
+      "links": {},
+      "events": {
+        "0xd8d928b0b50ca11d9dc273236b46f3526515b03602f71f3a6af4f45bd9fa9144": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "name",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogAddToken",
+          "type": "event"
+        },
+        "0x32c54f1e2ea75844ded7517e7dbcd3895da7cd0c28f9ab9f9cf6ecf5f83762c6": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "name",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogRemoveToken",
+          "type": "event"
+        },
+        "0x4a6dbfc867b179991dec22ff19960f0a94d8d9d891fc556f547764670340e8ae": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldName",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newName",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenNameChange",
+          "type": "event"
+        },
+        "0x53d878a6530e56c9bc96548fa0a8cae4f1d1f49c86b0e934c086b992ebb6998f": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSymbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newSymbol",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenSymbolChange",
+          "type": "event"
+        },
+        "0x5b19f79ac4e8cfa820815502e11615f1a449e28155dc289ec5cac1a11f908694": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldIpfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newIpfsHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenIpfsHashChange",
+          "type": "event"
+        },
+        "0xc3168fdc13112e44a031057dbf6c609b33353addb4d8037d24543e22cbfe2acd": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSwarmHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newSwarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenSwarmHashChange",
+          "type": "event"
+        }
+      },
+      "updated_at": 1502391794385,
+      "address": "0xf18e504561f4347bea557f3d4558f559dddbae7f"
+    },
+    "50": {
+      "links": {},
+      "events": {
+        "0xd8d928b0b50ca11d9dc273236b46f3526515b03602f71f3a6af4f45bd9fa9144": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "name",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogAddToken",
+          "type": "event"
+        },
+        "0x32c54f1e2ea75844ded7517e7dbcd3895da7cd0c28f9ab9f9cf6ecf5f83762c6": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "name",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "symbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "decimals",
+              "type": "uint8"
+            },
+            {
+              "indexed": false,
+              "name": "ipfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "swarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogRemoveToken",
+          "type": "event"
+        },
+        "0x4a6dbfc867b179991dec22ff19960f0a94d8d9d891fc556f547764670340e8ae": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldName",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newName",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenNameChange",
+          "type": "event"
+        },
+        "0x53d878a6530e56c9bc96548fa0a8cae4f1d1f49c86b0e934c086b992ebb6998f": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSymbol",
+              "type": "string"
+            },
+            {
+              "indexed": false,
+              "name": "newSymbol",
+              "type": "string"
+            }
+          ],
+          "name": "LogTokenSymbolChange",
+          "type": "event"
+        },
+        "0x5b19f79ac4e8cfa820815502e11615f1a449e28155dc289ec5cac1a11f908694": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldIpfsHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newIpfsHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenIpfsHashChange",
+          "type": "event"
+        },
+        "0xc3168fdc13112e44a031057dbf6c609b33353addb4d8037d24543e22cbfe2acd": {
+          "anonymous": false,
+          "inputs": [
+            {
+              "indexed": true,
+              "name": "token",
+              "type": "address"
+            },
+            {
+              "indexed": false,
+              "name": "oldSwarmHash",
+              "type": "bytes"
+            },
+            {
+              "indexed": false,
+              "name": "newSwarmHash",
+              "type": "bytes"
+            }
+          ],
+          "name": "LogTokenSwarmHashChange",
+          "type": "event"
+        }
+      },
+      "updated_at": 1503318938228,
+      "address": "0x0b1ba0af832d7c05fd64161e0db78e85978e8082"
+    }
+  },
+  "schema_version": "0.0.5",
+  "updated_at": 1503318938228
+}
diff --git a/packages/0x.js/src/artifacts/TokenTransferProxy.json b/packages/0x.js/src/artifacts/TokenTransferProxy.json
new file mode 100644
index 000000000..beeb16cfe
--- /dev/null
+++ b/packages/0x.js/src/artifacts/TokenTransferProxy.json
@@ -0,0 +1,174 @@
+{
+  "contract_name": "TokenTransferProxy",
+  "abi": [
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "token",
+          "type": "address"
+        },
+        {
+          "name": "from",
+          "type": "address"
+        },
+        {
+          "name": "to",
+          "type": "address"
+        },
+        {
+          "name": "value",
+          "type": "uint256"
+        }
+      ],
+      "name": "transferFrom",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "target",
+          "type": "address"
+        }
+      ],
+      "name": "addAuthorizedAddress",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "name": "authorities",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "target",
+          "type": "address"
+        }
+      ],
+      "name": "removeAuthorizedAddress",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "owner",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [
+        {
+          "name": "",
+          "type": "address"
+        }
+      ],
+      "name": "authorized",
+      "outputs": [
+        {
+          "name": "",
+          "type": "bool"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": true,
+      "inputs": [],
+      "name": "getAuthorizedAddresses",
+      "outputs": [
+        {
+          "name": "",
+          "type": "address[]"
+        }
+      ],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "constant": false,
+      "inputs": [
+        {
+          "name": "newOwner",
+          "type": "address"
+        }
+      ],
+      "name": "transferOwnership",
+      "outputs": [],
+      "payable": false,
+      "type": "function"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "target",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "caller",
+          "type": "address"
+        }
+      ],
+      "name": "LogAuthorizedAddressAdded",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "target",
+          "type": "address"
+        },
+        {
+          "indexed": true,
+          "name": "caller",
+          "type": "address"
+        }
+      ],
+      "name": "LogAuthorizedAddressRemoved",
+      "type": "event"
+    }
+  ],
+  "unlinked_binary": "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",
+  "networks": {},
+  "schema_version": "0.0.5",
+  "updated_at": 1503318938227
+}
diff --git a/packages/0x.js/src/bignumber_config.ts b/packages/0x.js/src/bignumber_config.ts
new file mode 100644
index 000000000..2d5214e6f
--- /dev/null
+++ b/packages/0x.js/src/bignumber_config.ts
@@ -0,0 +1,11 @@
+import BigNumber from 'bignumber.js';
+
+export const bigNumberConfigs = {
+    configure() {
+        // By default BigNumber's `toString` method converts to exponential notation if the value has
+        // more then 20 digits. We want to avoid this behavior, so we set EXPONENTIAL_AT to a high number
+        BigNumber.config({
+            EXPONENTIAL_AT: 1000,
+        });
+    },
+};
diff --git a/packages/0x.js/src/contract.ts b/packages/0x.js/src/contract.ts
new file mode 100644
index 000000000..1aacc65dc
--- /dev/null
+++ b/packages/0x.js/src/contract.ts
@@ -0,0 +1,80 @@
+import * as Web3 from 'web3';
+import * as _ from 'lodash';
+import promisify = require('es6-promisify');
+import {SchemaValidator, schemas} from '0x-json-schemas';
+import {AbiType} from './types';
+
+export class Contract implements Web3.ContractInstance {
+    public address: string;
+    public abi: Web3.ContractAbi;
+    private contract: Web3.ContractInstance;
+    private defaults: Partial<Web3.TxData>;
+    private validator: SchemaValidator;
+    // This class instance is going to be populated with functions and events depending on the ABI
+    // and we don't know their types in advance
+    [name: string]: any;
+    constructor(web3ContractInstance: Web3.ContractInstance, defaults: Partial<Web3.TxData>) {
+        this.contract = web3ContractInstance;
+        this.address = web3ContractInstance.address;
+        this.abi = web3ContractInstance.abi;
+        this.defaults = defaults;
+        this.populateEvents();
+        this.populateFunctions();
+        this.validator = new SchemaValidator();
+    }
+    private populateFunctions(): void {
+        const functionsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Function);
+        _.forEach(functionsAbi, (functionAbi: Web3.MethodAbi) => {
+            if (functionAbi.constant) {
+                const cbStyleCallFunction = this.contract[functionAbi.name].call;
+                this[functionAbi.name] = {
+                    callAsync: promisify(cbStyleCallFunction, this.contract),
+                };
+            } else {
+                const cbStyleFunction = this.contract[functionAbi.name];
+                const cbStyleEstimateGasFunction = this.contract[functionAbi.name].estimateGas;
+                this[functionAbi.name] = {
+                    estimateGasAsync: promisify(cbStyleEstimateGasFunction, this.contract),
+                    sendTransactionAsync: this.promisifyWithDefaultParams(cbStyleFunction),
+                };
+            }
+        });
+    }
+    private populateEvents(): void {
+        const eventsAbi = _.filter(this.abi, abiPart => abiPart.type === AbiType.Event);
+        _.forEach(eventsAbi, (eventAbi: Web3.EventAbi) => {
+            this[eventAbi.name] = this.contract[eventAbi.name];
+        });
+    }
+    private promisifyWithDefaultParams(fn: (...args: any[]) => void): (...args: any[]) => Promise<any> {
+        const promisifiedWithDefaultParams = (...args: any[]) => {
+            const promise = new Promise((resolve, reject) => {
+                const lastArg = args[args.length - 1];
+                let txData: Partial<Web3.TxData> = {};
+                if (this.isTxData(lastArg)) {
+                    txData = args.pop();
+                }
+                txData = {
+                    ...this.defaults,
+                    ...txData,
+                };
+                const callback = (err: Error, data: any) => {
+                    if (_.isNull(err)) {
+                        resolve(data);
+                    } else {
+                        reject(err);
+                    }
+                };
+                args.push(txData);
+                args.push(callback);
+                fn.apply(this.contract, args);
+            });
+            return promise;
+        };
+        return promisifiedWithDefaultParams;
+    }
+    private isTxData(lastArg: any): boolean {
+        const isValid = this.validator.isValid(lastArg, schemas.txDataSchema);
+        return isValid;
+    }
+}
diff --git a/packages/0x.js/src/contract_wrappers/contract_wrapper.ts b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
new file mode 100644
index 000000000..7997b1647
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
@@ -0,0 +1,152 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import {BlockAndLogStreamer, Block} from 'ethereumjs-blockstream';
+import {Web3Wrapper} from '../web3_wrapper';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {
+    ZeroExError,
+    InternalZeroExError,
+    Artifact,
+    LogWithDecodedArgs,
+    RawLog,
+    ContractEvents,
+    SubscriptionOpts,
+    IndexedFilterValues,
+    EventCallback,
+    BlockParamLiteral,
+    ContractEventArgs,
+} from '../types';
+import {constants} from '../utils/constants';
+import {intervalUtils} from '../utils/interval_utils';
+import {filterUtils} from '../utils/filter_utils';
+
+export class ContractWrapper {
+    protected _web3Wrapper: Web3Wrapper;
+    private _abiDecoder?: AbiDecoder;
+    private _blockAndLogStreamer: BlockAndLogStreamer|undefined;
+    private _blockAndLogStreamInterval: NodeJS.Timer;
+    private _filters: {[filterToken: string]: Web3.FilterObject};
+    private _filterCallbacks: {[filterToken: string]: EventCallback<ContractEventArgs>};
+    private _onLogAddedSubscriptionToken: string|undefined;
+    private _onLogRemovedSubscriptionToken: string|undefined;
+    constructor(web3Wrapper: Web3Wrapper, abiDecoder?: AbiDecoder) {
+        this._web3Wrapper = web3Wrapper;
+        this._abiDecoder = abiDecoder;
+        this._filters = {};
+        this._filterCallbacks = {};
+        this._blockAndLogStreamer = undefined;
+        this._onLogAddedSubscriptionToken = undefined;
+        this._onLogRemovedSubscriptionToken = undefined;
+    }
+    /**
+     * Cancels all existing subscriptions
+     */
+    public unsubscribeAll(): void {
+        const filterTokens = _.keys(this._filterCallbacks);
+        _.each(filterTokens, filterToken => {
+            this._unsubscribe(filterToken);
+        });
+    }
+    protected _unsubscribe(filterToken: string, err?: Error): void {
+        if (_.isUndefined(this._filters[filterToken])) {
+            throw new Error(ZeroExError.SubscriptionNotFound);
+        }
+        if (!_.isUndefined(err)) {
+            const callback = this._filterCallbacks[filterToken];
+            callback(err, undefined);
+        }
+        delete this._filters[filterToken];
+        delete this._filterCallbacks[filterToken];
+        if (_.isEmpty(this._filters)) {
+            this._stopBlockAndLogStream();
+        }
+    }
+    protected _subscribe<ArgsType extends ContractEventArgs>(
+        address: string, eventName: ContractEvents, indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi,
+        callback: EventCallback<ArgsType>): string {
+        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi);
+        if (_.isUndefined(this._blockAndLogStreamer)) {
+            this._startBlockAndLogStream();
+        }
+        const filterToken = filterUtils.generateUUID();
+        this._filters[filterToken] = filter;
+        this._filterCallbacks[filterToken] = callback;
+        return filterToken;
+    }
+    protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
+        address: string, eventName: ContractEvents, subscriptionOpts: SubscriptionOpts,
+        indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
+        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, subscriptionOpts);
+        const logs = await this._web3Wrapper.getLogsAsync(filter);
+        const logsWithDecodedArguments = _.map(logs, this._tryToDecodeLogOrNoop.bind(this));
+        return logsWithDecodedArguments;
+    }
+    protected _tryToDecodeLogOrNoop<ArgsType extends ContractEventArgs>(
+        log: Web3.LogEntry): LogWithDecodedArgs<ArgsType>|RawLog {
+        if (_.isUndefined(this._abiDecoder)) {
+            throw new Error(InternalZeroExError.NoAbiDecoder);
+        }
+        const logWithDecodedArgs = this._abiDecoder.tryToDecodeLogOrNoop(log);
+        return logWithDecodedArgs;
+    }
+    protected async _instantiateContractIfExistsAsync<ContractType extends Web3.ContractInstance>(
+        artifact: Artifact, addressIfExists?: string): Promise<ContractType> {
+        const contractInstance =
+            await this._web3Wrapper.getContractInstanceFromArtifactAsync<ContractType>(artifact, addressIfExists);
+        return contractInstance;
+    }
+    private _onLogStateChanged<ArgsType extends ContractEventArgs>(removed: boolean, log: Web3.LogEntry): void {
+        _.forEach(this._filters, (filter: Web3.FilterObject, filterToken: string) => {
+            if (filterUtils.matchesFilter(log, filter)) {
+                const decodedLog = this._tryToDecodeLogOrNoop(log) as LogWithDecodedArgs<ArgsType>;
+                const logEvent = {
+                    ...decodedLog,
+                    removed,
+                };
+                this._filterCallbacks[filterToken](null, logEvent);
+            }
+        });
+    }
+    private _startBlockAndLogStream(): void {
+        this._blockAndLogStreamer = new BlockAndLogStreamer(
+            this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper),
+            this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper),
+        );
+        const catchAllLogFilter = {};
+        this._blockAndLogStreamer.addLogFilter(catchAllLogFilter);
+        this._blockAndLogStreamInterval = intervalUtils.setAsyncExcludingInterval(
+            this._reconcileBlockAsync.bind(this), constants.DEFAULT_BLOCK_POLLING_INTERVAL,
+        );
+        let removed = false;
+        this._onLogAddedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogAdded(
+            this._onLogStateChanged.bind(this, removed),
+        );
+        removed = true;
+        this._onLogRemovedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogRemoved(
+            this._onLogStateChanged.bind(this, removed),
+        );
+    }
+    private _stopBlockAndLogStream(): void {
+        (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogAdded(
+            this._onLogAddedSubscriptionToken as string);
+        (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogRemoved(
+            this._onLogRemovedSubscriptionToken as string);
+        intervalUtils.clearAsyncExcludingInterval(this._blockAndLogStreamInterval);
+        delete this._blockAndLogStreamer;
+    }
+    private async _reconcileBlockAsync(): Promise<void> {
+        try {
+            const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
+            // We need to coerce to Block type cause Web3.Block includes types for mempool blocks
+            if (!_.isUndefined(this._blockAndLogStreamer)) {
+                // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
+                this._blockAndLogStreamer.reconcileNewBlock(latestBlock as any as Block);
+            }
+        } catch (err) {
+            const filterTokens = _.keys(this._filterCallbacks);
+            _.each(filterTokens, filterToken => {
+                this._unsubscribe(filterToken, err);
+            });
+        }
+    }
+}
diff --git a/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts b/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts
new file mode 100644
index 000000000..3cd2f0224
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts
@@ -0,0 +1,87 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {Web3Wrapper} from '../web3_wrapper';
+import {ContractWrapper} from './contract_wrapper';
+import {TokenWrapper} from './token_wrapper';
+import {EtherTokenContract, ZeroExError} from '../types';
+import {assert} from '../utils/assert';
+import {artifacts} from '../artifacts';
+
+/**
+ * This class includes all the functionality related to interacting with a wrapped Ether ERC20 token contract.
+ * The caller can convert ETH into the equivalent number of wrapped ETH ERC20 tokens and back.
+ */
+export class EtherTokenWrapper extends ContractWrapper {
+    private _etherTokenContractIfExists?: EtherTokenContract;
+    private _tokenWrapper: TokenWrapper;
+    private _contractAddressIfExists?: string;
+    constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper, contractAddressIfExists?: string) {
+        super(web3Wrapper);
+        this._tokenWrapper = tokenWrapper;
+        this._contractAddressIfExists = contractAddressIfExists;
+    }
+    /**
+     * Deposit ETH into the Wrapped ETH smart contract and issues the equivalent number of wrapped ETH tokens
+     * to the depositor address. These wrapped ETH tokens can be used in 0x trades and are redeemable for 1-to-1
+     * for ETH.
+     * @param   amountInWei      Amount of ETH in Wei the caller wishes to deposit.
+     * @param   depositor   The hex encoded user Ethereum address that would like to make the deposit.
+     * @return Transaction hash.
+     */
+    public async depositAsync(amountInWei: BigNumber, depositor: string): Promise<string> {
+        assert.isValidBaseUnitAmount('amountInWei', amountInWei);
+        await assert.isSenderAddressAsync('depositor', depositor, this._web3Wrapper);
+
+        const ethBalanceInWei = await this._web3Wrapper.getBalanceInWeiAsync(depositor);
+        assert.assert(ethBalanceInWei.gte(amountInWei), ZeroExError.InsufficientEthBalanceForDeposit);
+
+        const wethContract = await this._getEtherTokenContractAsync();
+        const txHash = await wethContract.deposit.sendTransactionAsync({
+            from: depositor,
+            value: amountInWei,
+        });
+        return txHash;
+    }
+    /**
+     * Withdraw ETH to the withdrawer's address from the wrapped ETH smart contract in exchange for the
+     * equivalent number of wrapped ETH tokens.
+     * @param   amountInWei  Amount of ETH in Wei the caller wishes to withdraw.
+     * @param   withdrawer   The hex encoded user Ethereum address that would like to make the withdrawl.
+     * @return Transaction hash.
+     */
+    public async withdrawAsync(amountInWei: BigNumber, withdrawer: string): Promise<string> {
+        assert.isValidBaseUnitAmount('amountInWei', amountInWei);
+        await assert.isSenderAddressAsync('withdrawer', withdrawer, this._web3Wrapper);
+
+        const wethContractAddress = await this.getContractAddressAsync();
+        const WETHBalanceInBaseUnits = await this._tokenWrapper.getBalanceAsync(wethContractAddress, withdrawer);
+        assert.assert(WETHBalanceInBaseUnits.gte(amountInWei), ZeroExError.InsufficientWEthBalanceForWithdrawal);
+
+        const wethContract = await this._getEtherTokenContractAsync();
+        const txHash = await wethContract.withdraw.sendTransactionAsync(amountInWei, {
+            from: withdrawer,
+        });
+        return txHash;
+    }
+    /**
+     * Retrieves the Wrapped Ether token contract address
+     * @return  The Wrapped Ether token contract address
+     */
+    public async getContractAddressAsync(): Promise<string> {
+        const wethContract = await this._getEtherTokenContractAsync();
+        return wethContract.address;
+    }
+    private _invalidateContractInstance(): void {
+        delete this._etherTokenContractIfExists;
+    }
+    private async _getEtherTokenContractAsync(): Promise<EtherTokenContract> {
+        if (!_.isUndefined(this._etherTokenContractIfExists)) {
+            return this._etherTokenContractIfExists;
+        }
+        const contractInstance = await this._instantiateContractIfExistsAsync<EtherTokenContract>(
+            artifacts.EtherTokenArtifact, this._contractAddressIfExists,
+        );
+        this._etherTokenContractIfExists = contractInstance as EtherTokenContract;
+        return this._etherTokenContractIfExists;
+    }
+}
diff --git a/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts b/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
new file mode 100644
index 000000000..fe0c5bc00
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
@@ -0,0 +1,866 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {schemas} from '0x-json-schemas';
+import {Web3Wrapper} from '../web3_wrapper';
+import {
+    ECSignature,
+    ExchangeContract,
+    ExchangeContractErrCodes,
+    ExchangeContractErrs,
+    ZeroExError,
+    OrderValues,
+    OrderAddresses,
+    Order,
+    SignedOrder,
+    ExchangeEvents,
+    SubscriptionOpts,
+    IndexedFilterValues,
+    OrderCancellationRequest,
+    OrderFillRequest,
+    LogErrorContractEventArgs,
+    LogFillContractEventArgs,
+    LogCancelContractEventArgs,
+    LogWithDecodedArgs,
+    MethodOpts,
+    ValidateOrderFillableOpts,
+    OrderTransactionOpts,
+    RawLog,
+    EventCallback,
+    ExchangeContractEventArgs,
+    DecodedLogArgs,
+} from '../types';
+import {assert} from '../utils/assert';
+import {utils} from '../utils/utils';
+import {OrderValidationUtils} from '../utils/order_validation_utils';
+import {ContractWrapper} from './contract_wrapper';
+import {TokenWrapper} from './token_wrapper';
+import {decorators} from '../utils/decorators';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {ExchangeTransferSimulator} from '../utils/exchange_transfer_simulator';
+import {artifacts} from '../artifacts';
+
+const SHOULD_VALIDATE_BY_DEFAULT = true;
+
+/**
+ * This class includes all the functionality related to calling methods and subscribing to
+ * events of the 0x Exchange smart contract.
+ */
+export class ExchangeWrapper extends ContractWrapper {
+    private _exchangeContractIfExists?: ExchangeContract;
+    private _orderValidationUtils: OrderValidationUtils;
+    private _tokenWrapper: TokenWrapper;
+    private _exchangeContractErrCodesToMsg = {
+        [ExchangeContractErrCodes.ERROR_FILL_EXPIRED]: ExchangeContractErrs.OrderFillExpired,
+        [ExchangeContractErrCodes.ERROR_CANCEL_EXPIRED]: ExchangeContractErrs.OrderFillExpired,
+        [ExchangeContractErrCodes.ERROR_FILL_NO_VALUE]: ExchangeContractErrs.OrderRemainingFillAmountZero,
+        [ExchangeContractErrCodes.ERROR_CANCEL_NO_VALUE]: ExchangeContractErrs.OrderRemainingFillAmountZero,
+        [ExchangeContractErrCodes.ERROR_FILL_TRUNCATION]: ExchangeContractErrs.OrderFillRoundingError,
+        [ExchangeContractErrCodes.ERROR_FILL_BALANCE_ALLOWANCE]: ExchangeContractErrs.FillBalanceAllowanceError,
+    };
+    private _contractAddressIfExists?: string;
+    private static _getOrderAddressesAndValues(order: Order): [OrderAddresses, OrderValues] {
+        const orderAddresses: OrderAddresses = [
+            order.maker,
+            order.taker,
+            order.makerTokenAddress,
+            order.takerTokenAddress,
+            order.feeRecipient,
+        ];
+        const orderValues: OrderValues = [
+            order.makerTokenAmount,
+            order.takerTokenAmount,
+            order.makerFee,
+            order.takerFee,
+            order.expirationUnixTimestampSec,
+            order.salt,
+        ];
+        return [orderAddresses, orderValues];
+    }
+    constructor(web3Wrapper: Web3Wrapper, abiDecoder: AbiDecoder,
+                tokenWrapper: TokenWrapper, contractAddressIfExists?: string) {
+        super(web3Wrapper, abiDecoder);
+        this._tokenWrapper = tokenWrapper;
+        this._orderValidationUtils = new OrderValidationUtils(tokenWrapper, this);
+        this._contractAddressIfExists = contractAddressIfExists;
+    }
+    /**
+     * Returns the unavailable takerAmount of an order. Unavailable amount is defined as the total
+     * amount that has been filled or cancelled. The remaining takerAmount can be calculated by
+     * subtracting the unavailable amount from the total order takerAmount.
+     * @param   orderHash               The hex encoded orderHash for which you would like to retrieve the
+     *                                  unavailable takerAmount.
+     * @param   methodOpts              Optional arguments this method accepts.
+     * @return  The amount of the order (in taker tokens) that has either been filled or canceled.
+     */
+    public async getUnavailableTakerAmountAsync(orderHash: string,
+                                                methodOpts?: MethodOpts): Promise<BigNumber> {
+        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
+
+        const exchangeContract = await this._getExchangeContractAsync();
+        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
+        let unavailableTakerTokenAmount = await exchangeContract.getUnavailableTakerTokenAmount.callAsync(
+            orderHash, defaultBlock,
+        );
+        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
+        unavailableTakerTokenAmount = new BigNumber(unavailableTakerTokenAmount);
+        return unavailableTakerTokenAmount;
+    }
+    /**
+     * Retrieve the takerAmount of an order that has already been filled.
+     * @param   orderHash    The hex encoded orderHash for which you would like to retrieve the filled takerAmount.
+     * @param   methodOpts   Optional arguments this method accepts.
+     * @return  The amount of the order (in taker tokens) that has already been filled.
+     */
+    public async getFilledTakerAmountAsync(orderHash: string, methodOpts?: MethodOpts): Promise<BigNumber> {
+        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
+
+        const exchangeContract = await this._getExchangeContractAsync();
+        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
+        let fillAmountInBaseUnits = await exchangeContract.filled.callAsync(orderHash, defaultBlock);
+        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
+        fillAmountInBaseUnits = new BigNumber(fillAmountInBaseUnits);
+        return fillAmountInBaseUnits;
+    }
+    /**
+     * Retrieve the takerAmount of an order that has been cancelled.
+     * @param   orderHash    The hex encoded orderHash for which you would like to retrieve the
+     *                       cancelled takerAmount.
+     * @param   methodOpts   Optional arguments this method accepts.
+     * @return  The amount of the order (in taker tokens) that has been cancelled.
+     */
+    public async getCanceledTakerAmountAsync(orderHash: string, methodOpts?: MethodOpts): Promise<BigNumber> {
+        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
+
+        const exchangeContract = await this._getExchangeContractAsync();
+        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
+        let cancelledAmountInBaseUnits = await exchangeContract.cancelled.callAsync(orderHash, defaultBlock);
+        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
+        cancelledAmountInBaseUnits = new BigNumber(cancelledAmountInBaseUnits);
+        return cancelledAmountInBaseUnits;
+    }
+    /**
+     * Fills a signed order with an amount denominated in baseUnits of the taker token.
+     * Since the order in which transactions are included in the next block is indeterminate, race-conditions
+     * could arise where a users balance or allowance changes before the fillOrder executes. Because of this,
+     * we allow you to specify `shouldThrowOnInsufficientBalanceOrAllowance`.
+     * If false, the smart contract will not throw if the parties
+     * do not have sufficient balances/allowances, preserving gas costs. Setting it to true forgoes this check
+     * and causes the smart contract to throw (using all the gas supplied) instead.
+     * @param   signedOrder                                 An object that conforms to the SignedOrder interface.
+     * @param   fillTakerTokenAmount                        The amount of the order (in taker tokens baseUnits) that
+     *                                                      you wish to fill.
+     * @param   shouldThrowOnInsufficientBalanceOrAllowance Whether or not you wish for the contract call to throw
+     *                                                      if upon execution the tokens cannot be transferred.
+     * @param   takerAddress                                The user Ethereum address who would like to fill this order.
+     *                                                      Must be available via the supplied Web3.Provider
+     *                                                      passed to 0x.js.
+     * @param   orderTransactionOpts                        Optional arguments this method accepts.
+     * @return  Transaction hash.
+     */
+    @decorators.contractCallErrorHandler
+    public async fillOrderAsync(signedOrder: SignedOrder, fillTakerTokenAmount: BigNumber,
+                                shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                                takerAddress: string,
+                                orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
+        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
+        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
+
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
+            SHOULD_VALIDATE_BY_DEFAULT :
+            orderTransactionOpts.shouldValidate;
+        if (shouldValidate) {
+            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
+                exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
+        }
+
+        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);
+
+        const gas = await exchangeInstance.fillOrder.estimateGasAsync(
+            orderAddresses,
+            orderValues,
+            fillTakerTokenAmount,
+            shouldThrowOnInsufficientBalanceOrAllowance,
+            signedOrder.ecSignature.v,
+            signedOrder.ecSignature.r,
+            signedOrder.ecSignature.s,
+            {
+                from: takerAddress,
+            },
+        );
+        const txHash: string = await exchangeInstance.fillOrder.sendTransactionAsync(
+            orderAddresses,
+            orderValues,
+            fillTakerTokenAmount,
+            shouldThrowOnInsufficientBalanceOrAllowance,
+            signedOrder.ecSignature.v,
+            signedOrder.ecSignature.r,
+            signedOrder.ecSignature.s,
+            {
+                from: takerAddress,
+                gas,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Sequentially and atomically fills signedOrders up to the specified takerTokenFillAmount.
+     * If the fill amount is reached - it succeeds and does not fill the rest of the orders.
+     * If fill amount is not reached - it fills as much of the fill amount as possible and succeeds.
+     * @param   signedOrders                                The array of signedOrders that you would like to fill until
+     *                                                      takerTokenFillAmount is reached.
+     * @param   fillTakerTokenAmount                        The total amount of the takerTokens you would like to fill.
+     * @param   shouldThrowOnInsufficientBalanceOrAllowance Whether or not you wish for the contract call to throw if
+     *                                                      upon execution any of the tokens cannot be transferred.
+     *                                                      If set to false, the call will continue to fill subsequent
+     *                                                      signedOrders even when some cannot be filled.
+     * @param   takerAddress                                The user Ethereum address who would like to fill these
+     *                                                      orders. Must be available via the supplied Web3.Provider
+     *                                                      passed to 0x.js.
+     * @param   orderTransactionOpts                        Optional arguments this method accepts.
+     * @return  Transaction hash.
+     */
+    @decorators.contractCallErrorHandler
+    public async fillOrdersUpToAsync(signedOrders: SignedOrder[], fillTakerTokenAmount: BigNumber,
+                                     shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                                     takerAddress: string,
+                                     orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
+        const takerTokenAddresses = _.map(signedOrders, signedOrder => signedOrder.takerTokenAddress);
+        assert.hasAtMostOneUniqueValue(takerTokenAddresses,
+                                       ExchangeContractErrs.MultipleTakerTokensInFillUpToDisallowed);
+        const exchangeContractAddresses = _.map(signedOrders, signedOrder => signedOrder.exchangeContractAddress);
+        assert.hasAtMostOneUniqueValue(exchangeContractAddresses,
+                                       ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress);
+        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
+        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
+        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
+
+        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
+            SHOULD_VALIDATE_BY_DEFAULT :
+            orderTransactionOpts.shouldValidate;
+        if (shouldValidate) {
+            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            for (const signedOrder of signedOrders) {
+                await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
+                    exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
+            }
+        }
+
+        if (_.isEmpty(signedOrders)) {
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
+        }
+
+        const orderAddressesValuesAndSignatureArray = _.map(signedOrders, signedOrder => {
+            return [
+                ...ExchangeWrapper._getOrderAddressesAndValues(signedOrder),
+                signedOrder.ecSignature.v,
+                signedOrder.ecSignature.r,
+                signedOrder.ecSignature.s,
+            ];
+        });
+        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
+        const [orderAddressesArray, orderValuesArray, vArray, rArray, sArray] = _.unzip<any>(
+            orderAddressesValuesAndSignatureArray,
+        );
+
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const gas = await exchangeInstance.fillOrdersUpTo.estimateGasAsync(
+            orderAddressesArray,
+            orderValuesArray,
+            fillTakerTokenAmount,
+            shouldThrowOnInsufficientBalanceOrAllowance,
+            vArray,
+            rArray,
+            sArray,
+            {
+                from: takerAddress,
+            },
+        );
+        const txHash = await exchangeInstance.fillOrdersUpTo.sendTransactionAsync(
+            orderAddressesArray,
+            orderValuesArray,
+            fillTakerTokenAmount,
+            shouldThrowOnInsufficientBalanceOrAllowance,
+            vArray,
+            rArray,
+            sArray,
+            {
+                from: takerAddress,
+                gas,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Batch version of fillOrderAsync.
+     * Executes multiple fills atomically in a single transaction.
+     * If shouldThrowOnInsufficientBalanceOrAllowance is set to false, it will continue filling subsequent orders even
+     * when earlier ones fail.
+     * When shouldThrowOnInsufficientBalanceOrAllowance is set to true, if any fill fails, the entire batch fails.
+     * @param   orderFillRequests                               An array of objects that conform to the
+     *                                                          OrderFillRequest interface.
+     * @param   shouldThrowOnInsufficientBalanceOrAllowance     Whether or not you wish for the contract call to throw
+     *                                                          if upon execution any of the tokens cannot be
+     *                                                          transferred. If set to false, the call will continue to
+     *                                                          fill subsequent signedOrders even when some
+     *                                                          cannot be filled.
+     * @param   takerAddress                                    The user Ethereum address who would like to fill
+     *                                                          these orders. Must be available via the supplied
+     *                                                          Web3.Provider passed to 0x.js.
+     * @param   orderTransactionOpts                            Optional arguments this method accepts.
+     * @return  Transaction hash.
+     */
+    @decorators.contractCallErrorHandler
+    public async batchFillOrdersAsync(orderFillRequests: OrderFillRequest[],
+                                      shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                                      takerAddress: string,
+                                      orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+        assert.doesConformToSchema('orderFillRequests', orderFillRequests, schemas.orderFillRequestsSchema);
+        const exchangeContractAddresses = _.map(
+            orderFillRequests,
+            orderFillRequest => orderFillRequest.signedOrder.exchangeContractAddress,
+        );
+        assert.hasAtMostOneUniqueValue(exchangeContractAddresses,
+                                       ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress);
+        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
+        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
+        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
+            SHOULD_VALIDATE_BY_DEFAULT :
+            orderTransactionOpts.shouldValidate;
+        if (shouldValidate) {
+            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            for (const orderFillRequest of orderFillRequests) {
+                await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
+                    exchangeTradeEmulator, orderFillRequest.signedOrder, orderFillRequest.takerTokenFillAmount,
+                    takerAddress, zrxTokenAddress,
+                );
+            }
+        }
+        if (_.isEmpty(orderFillRequests)) {
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
+        }
+
+        const orderAddressesValuesAmountsAndSignatureArray = _.map(orderFillRequests, orderFillRequest => {
+            return [
+                ...ExchangeWrapper._getOrderAddressesAndValues(orderFillRequest.signedOrder),
+                orderFillRequest.takerTokenFillAmount,
+                orderFillRequest.signedOrder.ecSignature.v,
+                orderFillRequest.signedOrder.ecSignature.r,
+                orderFillRequest.signedOrder.ecSignature.s,
+            ];
+        });
+        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
+        const [orderAddressesArray, orderValuesArray, fillTakerTokenAmounts, vArray, rArray, sArray] = _.unzip<any>(
+            orderAddressesValuesAmountsAndSignatureArray,
+        );
+
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const gas = await exchangeInstance.batchFillOrders.estimateGasAsync(
+            orderAddressesArray,
+            orderValuesArray,
+            fillTakerTokenAmounts,
+            shouldThrowOnInsufficientBalanceOrAllowance,
+            vArray,
+            rArray,
+            sArray,
+            {
+                from: takerAddress,
+            },
+        );
+        const txHash = await exchangeInstance.batchFillOrders.sendTransactionAsync(
+            orderAddressesArray,
+            orderValuesArray,
+            fillTakerTokenAmounts,
+            shouldThrowOnInsufficientBalanceOrAllowance,
+            vArray,
+            rArray,
+            sArray,
+            {
+                from: takerAddress,
+                gas,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Attempts to fill a specific amount of an order. If the entire amount specified cannot be filled,
+     * the fill order is abandoned.
+     * @param   signedOrder             An object that conforms to the SignedOrder interface. The
+     *                                  signedOrder you wish to fill.
+     * @param   fillTakerTokenAmount    The total amount of the takerTokens you would like to fill.
+     * @param   takerAddress            The user Ethereum address who would like to fill this order.
+     *                                  Must be available via the supplied Web3.Provider passed to 0x.js.
+     * @param   orderTransactionOpts    Optional arguments this method accepts.
+     * @return  Transaction hash.
+     */
+    @decorators.contractCallErrorHandler
+    public async fillOrKillOrderAsync(signedOrder: SignedOrder, fillTakerTokenAmount: BigNumber,
+                                      takerAddress: string,
+                                      orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
+        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
+
+        const exchangeInstance = await this._getExchangeContractAsync();
+
+        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
+            SHOULD_VALIDATE_BY_DEFAULT :
+            orderTransactionOpts.shouldValidate;
+        if (shouldValidate) {
+            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
+                exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
+        }
+
+        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);
+
+        const gas = await exchangeInstance.fillOrKillOrder.estimateGasAsync(
+            orderAddresses,
+            orderValues,
+            fillTakerTokenAmount,
+            signedOrder.ecSignature.v,
+            signedOrder.ecSignature.r,
+            signedOrder.ecSignature.s,
+            {
+                from: takerAddress,
+            },
+        );
+        const txHash = await exchangeInstance.fillOrKillOrder.sendTransactionAsync(
+            orderAddresses,
+            orderValues,
+            fillTakerTokenAmount,
+            signedOrder.ecSignature.v,
+            signedOrder.ecSignature.r,
+            signedOrder.ecSignature.s,
+            {
+                from: takerAddress,
+                gas,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Batch version of fillOrKill. Allows a taker to specify a batch of orders that will either be atomically
+     * filled (each to the specified fillAmount) or aborted.
+     * @param   orderFillRequests           An array of objects that conform to the OrderFillRequest interface.
+     * @param   takerAddress                The user Ethereum address who would like to fill there orders.
+     *                                      Must be available via the supplied Web3.Provider passed to 0x.js.
+     * @param   orderTransactionOpts        Optional arguments this method accepts.
+     * @return  Transaction hash.
+     */
+    @decorators.contractCallErrorHandler
+    public async batchFillOrKillAsync(orderFillRequests: OrderFillRequest[],
+                                      takerAddress: string,
+                                      orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+        assert.doesConformToSchema('orderFillRequests', orderFillRequests,
+                                   schemas.orderFillRequestsSchema);
+        const exchangeContractAddresses = _.map(
+            orderFillRequests,
+            orderFillRequest => orderFillRequest.signedOrder.exchangeContractAddress,
+        );
+        assert.hasAtMostOneUniqueValue(exchangeContractAddresses,
+                                       ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress);
+        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
+        if (_.isEmpty(orderFillRequests)) {
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
+        }
+        const exchangeInstance = await this._getExchangeContractAsync();
+
+        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
+            SHOULD_VALIDATE_BY_DEFAULT :
+            orderTransactionOpts.shouldValidate;
+        if (shouldValidate) {
+            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            for (const orderFillRequest of orderFillRequests) {
+                await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
+                    exchangeTradeEmulator, orderFillRequest.signedOrder, orderFillRequest.takerTokenFillAmount,
+                    takerAddress, zrxTokenAddress,
+                );
+            }
+        }
+
+        const orderAddressesValuesAndTakerTokenFillAmounts = _.map(orderFillRequests, request => {
+            return [
+                ...ExchangeWrapper._getOrderAddressesAndValues(request.signedOrder),
+                request.takerTokenFillAmount,
+                request.signedOrder.ecSignature.v,
+                request.signedOrder.ecSignature.r,
+                request.signedOrder.ecSignature.s,
+            ];
+        });
+
+        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
+        const [orderAddresses, orderValues, fillTakerTokenAmounts, vParams, rParams, sParams] =
+              _.unzip<any>(orderAddressesValuesAndTakerTokenFillAmounts);
+
+        const gas = await exchangeInstance.batchFillOrKillOrders.estimateGasAsync(
+            orderAddresses,
+            orderValues,
+            fillTakerTokenAmounts,
+            vParams,
+            rParams,
+            sParams,
+            {
+                from: takerAddress,
+            },
+        );
+        const txHash = await exchangeInstance.batchFillOrKillOrders.sendTransactionAsync(
+            orderAddresses,
+            orderValues,
+            fillTakerTokenAmounts,
+            vParams,
+            rParams,
+            sParams,
+            {
+                from: takerAddress,
+                gas,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Cancel a given fill amount of an order. Cancellations are cumulative.
+     * @param   order                   An object that conforms to the Order or SignedOrder interface.
+     *                                  The order you would like to cancel.
+     * @param   cancelTakerTokenAmount  The amount (specified in taker tokens) that you would like to cancel.
+     * @param   transactionOpts         Optional arguments this method accepts.
+     * @return  Transaction hash.
+     */
+    @decorators.contractCallErrorHandler
+    public async cancelOrderAsync(order: Order|SignedOrder,
+                                  cancelTakerTokenAmount: BigNumber,
+                                  orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+        assert.doesConformToSchema('order', order, schemas.orderSchema);
+        assert.isValidBaseUnitAmount('takerTokenCancelAmount', cancelTakerTokenAmount);
+        await assert.isSenderAddressAsync('order.maker', order.maker, this._web3Wrapper);
+
+        const exchangeInstance = await this._getExchangeContractAsync();
+
+        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
+            SHOULD_VALIDATE_BY_DEFAULT :
+            orderTransactionOpts.shouldValidate;
+        if (shouldValidate) {
+            const orderHash = utils.getOrderHashHex(order);
+            const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
+            await this._orderValidationUtils.validateCancelOrderThrowIfInvalidAsync(
+                order, cancelTakerTokenAmount, unavailableTakerTokenAmount);
+        }
+
+        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(order);
+        const gas = await exchangeInstance.cancelOrder.estimateGasAsync(
+            orderAddresses,
+            orderValues,
+            cancelTakerTokenAmount,
+            {
+                from: order.maker,
+            },
+        );
+        const txHash = await exchangeInstance.cancelOrder.sendTransactionAsync(
+            orderAddresses,
+            orderValues,
+            cancelTakerTokenAmount,
+            {
+                from: order.maker,
+                gas,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Batch version of cancelOrderAsync. Atomically cancels multiple orders in a single transaction.
+     * All orders must be from the same maker.
+     * @param   orderCancellationRequests   An array of objects that conform to the OrderCancellationRequest
+     *                                      interface.
+     * @param   transactionOpts             Optional arguments this method accepts.
+     * @return  Transaction hash.
+     */
+    @decorators.contractCallErrorHandler
+    public async batchCancelOrdersAsync(orderCancellationRequests: OrderCancellationRequest[],
+                                        orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+        assert.doesConformToSchema('orderCancellationRequests', orderCancellationRequests,
+                                   schemas.orderCancellationRequestsSchema);
+        const exchangeContractAddresses = _.map(
+            orderCancellationRequests,
+            orderCancellationRequest => orderCancellationRequest.order.exchangeContractAddress,
+        );
+        assert.hasAtMostOneUniqueValue(exchangeContractAddresses,
+                                       ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress);
+        const makers = _.map(orderCancellationRequests, cancellationRequest => cancellationRequest.order.maker);
+        assert.hasAtMostOneUniqueValue(makers, ExchangeContractErrs.MultipleMakersInSingleCancelBatchDisallowed);
+        const maker = makers[0];
+        await assert.isSenderAddressAsync('maker', maker, this._web3Wrapper);
+        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
+            SHOULD_VALIDATE_BY_DEFAULT :
+            orderTransactionOpts.shouldValidate;
+        if (shouldValidate) {
+            for (const orderCancellationRequest of orderCancellationRequests) {
+                const orderHash = utils.getOrderHashHex(orderCancellationRequest.order);
+                const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
+                await this._orderValidationUtils.validateCancelOrderThrowIfInvalidAsync(
+                    orderCancellationRequest.order, orderCancellationRequest.takerTokenCancelAmount,
+                    unavailableTakerTokenAmount,
+                );
+            }
+
+        }
+        if (_.isEmpty(orderCancellationRequests)) {
+            throw new Error(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
+        }
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const orderAddressesValuesAndTakerTokenCancelAmounts = _.map(orderCancellationRequests, cancellationRequest => {
+            return [
+                ...ExchangeWrapper._getOrderAddressesAndValues(cancellationRequest.order),
+                cancellationRequest.takerTokenCancelAmount,
+            ];
+        });
+        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
+        const [orderAddresses, orderValues, cancelTakerTokenAmounts] =
+            _.unzip<any>(orderAddressesValuesAndTakerTokenCancelAmounts);
+        const gas = await exchangeInstance.batchCancelOrders.estimateGasAsync(
+            orderAddresses,
+            orderValues,
+            cancelTakerTokenAmounts,
+            {
+                from: maker,
+            },
+        );
+        const txHash = await exchangeInstance.batchCancelOrders.sendTransactionAsync(
+            orderAddresses,
+            orderValues,
+            cancelTakerTokenAmounts,
+            {
+                from: maker,
+                gas,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Subscribe to an event type emitted by the Exchange contract.
+     * @param   eventName           The exchange contract event you would like to subscribe to.
+     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
+     *                              the value is the value you are interested in. E.g `{maker: aUserAddressHex}`
+     * @param   callback            Callback that gets called when a log is added/removed
+     * @return Subscription token used later to unsubscribe
+     */
+    public async subscribeAsync<ArgsType extends ExchangeContractEventArgs>(
+        eventName: ExchangeEvents, indexFilterValues: IndexedFilterValues,
+        callback: EventCallback<ArgsType>): Promise<string> {
+        assert.doesBelongToStringEnum('eventName', eventName, ExchangeEvents);
+        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
+        assert.isFunction('callback', callback);
+        const exchangeContractAddress = await this.getContractAddressAsync();
+        const subscriptionToken = this._subscribe<ArgsType>(
+            exchangeContractAddress, eventName, indexFilterValues, artifacts.ExchangeArtifact.abi, callback,
+        );
+        return subscriptionToken;
+    }
+    /**
+     * Cancel a subscription
+     * @param   subscriptionToken Subscription token returned by `subscribe()`
+     */
+    public unsubscribe(subscriptionToken: string): void {
+        this._unsubscribe(subscriptionToken);
+    }
+    /**
+     * Gets historical logs without creating a subscription
+     * @param   eventName           The exchange contract event you would like to subscribe to.
+     * @param   subscriptionOpts    Subscriptions options that let you configure the subscription.
+     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
+     *                              the value is the value you are interested in. E.g `{_from: aUserAddressHex}`
+     * @return  Array of logs that match the parameters
+     */
+    public async getLogsAsync<ArgsType extends ExchangeContractEventArgs>(
+        eventName: ExchangeEvents, subscriptionOpts: SubscriptionOpts, indexFilterValues: IndexedFilterValues,
+    ): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
+        assert.doesBelongToStringEnum('eventName', eventName, ExchangeEvents);
+        assert.doesConformToSchema('subscriptionOpts', subscriptionOpts, schemas.subscriptionOptsSchema);
+        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
+        const exchangeContractAddress = await this.getContractAddressAsync();
+        const logs = await this._getLogsAsync<ArgsType>(
+            exchangeContractAddress, eventName, subscriptionOpts, indexFilterValues, artifacts.ExchangeArtifact.abi,
+        );
+        return logs;
+    }
+    /**
+     * Retrieves the Ethereum address of the Exchange contract deployed on the network
+     * that the user-passed web3 provider is connected to.
+     * @returns The Ethereum address of the Exchange contract being used.
+     */
+    public async getContractAddressAsync(): Promise<string> {
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const exchangeAddress = exchangeInstance.address;
+        return exchangeAddress;
+    }
+    /**
+     * Checks if order is still fillable and throws an error otherwise. Useful for orderbook
+     * pruning where you want to remove stale orders without knowing who the taker will be.
+     * @param   signedOrder     An object that conforms to the SignedOrder interface. The
+     *                          signedOrder you wish to validate.
+     * @param   opts            An object that conforms to the ValidateOrderFillableOpts
+     *                          interface. Allows specifying a specific fillTakerTokenAmount
+     *                          to validate for.
+     */
+    public async validateOrderFillableOrThrowAsync(
+        signedOrder: SignedOrder, opts?: ValidateOrderFillableOpts,
+    ): Promise<void> {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+        const expectedFillTakerTokenAmount = !_.isUndefined(opts) ? opts.expectedFillTakerTokenAmount : undefined;
+        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+        await this._orderValidationUtils.validateOrderFillableOrThrowAsync(
+            exchangeTradeEmulator, signedOrder, zrxTokenAddress, expectedFillTakerTokenAmount,
+        );
+    }
+    /**
+     * Checks if order fill will succeed and throws an error otherwise.
+     * @param   signedOrder             An object that conforms to the SignedOrder interface. The
+     *                                  signedOrder you wish to fill.
+     * @param   fillTakerTokenAmount    The total amount of the takerTokens you would like to fill.
+     * @param   takerAddress            The user Ethereum address who would like to fill this order.
+     *                                  Must be available via the supplied Web3.Provider passed to 0x.js.
+     */
+    public async validateFillOrderThrowIfInvalidAsync(signedOrder: SignedOrder,
+                                                      fillTakerTokenAmount: BigNumber,
+                                                      takerAddress: string): Promise<void> {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
+        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
+        const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+        await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
+            exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
+    }
+    /**
+     * Checks if cancelling a given order will succeed and throws an informative error if it won't.
+     * @param   order                   An object that conforms to the Order or SignedOrder interface.
+     *                                  The order you would like to cancel.
+     * @param   cancelTakerTokenAmount  The amount (specified in taker tokens) that you would like to cancel.
+     */
+    public async validateCancelOrderThrowIfInvalidAsync(
+        order: Order, cancelTakerTokenAmount: BigNumber): Promise<void> {
+        assert.doesConformToSchema('order', order, schemas.orderSchema);
+        assert.isValidBaseUnitAmount('cancelTakerTokenAmount', cancelTakerTokenAmount);
+        const orderHash = utils.getOrderHashHex(order);
+        const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
+        await this._orderValidationUtils.validateCancelOrderThrowIfInvalidAsync(
+            order, cancelTakerTokenAmount, unavailableTakerTokenAmount);
+    }
+    /**
+     * Checks if calling fillOrKill on a given order will succeed and throws an informative error if it won't.
+     * @param   signedOrder             An object that conforms to the SignedOrder interface. The
+     *                                  signedOrder you wish to fill.
+     * @param   fillTakerTokenAmount    The total amount of the takerTokens you would like to fill.
+     * @param   takerAddress            The user Ethereum address who would like to fill this order.
+     *                                  Must be available via the supplied Web3.Provider passed to 0x.js.
+     */
+    public async validateFillOrKillOrderThrowIfInvalidAsync(signedOrder: SignedOrder,
+                                                            fillTakerTokenAmount: BigNumber,
+                                                            takerAddress: string): Promise<void> {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
+        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
+        const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+        await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
+            exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
+    }
+    /**
+     * Checks if rounding error will be > 0.1% when computing makerTokenAmount by doing:
+     * `(fillTakerTokenAmount * makerTokenAmount) / takerTokenAmount`.
+     * 0x Protocol does not accept any trades that result in large rounding errors. This means that tokens with few or
+     * no decimals can only be filled in quantities and ratios that avoid large rounding errors.
+     * @param   fillTakerTokenAmount   The amount of the order (in taker tokens baseUnits) that you wish to fill.
+     * @param   takerTokenAmount       The order size on the taker side
+     * @param   makerTokenAmount       The order size on the maker side
+     */
+    public async isRoundingErrorAsync(fillTakerTokenAmount: BigNumber,
+                                      takerTokenAmount: BigNumber,
+                                      makerTokenAmount: BigNumber): Promise<boolean> {
+        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
+        assert.isValidBaseUnitAmount('takerTokenAmount', takerTokenAmount);
+        assert.isValidBaseUnitAmount('makerTokenAmount', makerTokenAmount);
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const isRoundingError = await exchangeInstance.isRoundingError.callAsync(
+            fillTakerTokenAmount, takerTokenAmount, makerTokenAmount,
+        );
+        return isRoundingError;
+    }
+    /**
+     * Checks if logs contain LogError, which is emmited by Exchange contract on transaction failure.
+     * @param   logs   Transaction logs as returned by `zeroEx.awaitTransactionMinedAsync`
+     */
+    public throwLogErrorsAsErrors(logs: Array<LogWithDecodedArgs<DecodedLogArgs>|Web3.LogEntry>): void {
+        const errLog = _.find(logs, {
+            event: ExchangeEvents.LogError,
+        }) as LogWithDecodedArgs<LogErrorContractEventArgs>|undefined;
+        if (!_.isUndefined(errLog)) {
+            const logArgs = errLog.args;
+            const errCode = logArgs.errorId.toNumber();
+            const errMessage = this._exchangeContractErrCodesToMsg[errCode];
+            throw new Error(errMessage);
+        }
+    }
+    /**
+     * Returns the ZRX token address used by the exchange contract.
+     * @return Address of ZRX token
+     */
+    public async getZRXTokenAddressAsync(): Promise<string> {
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const ZRXtokenAddress = await exchangeInstance.ZRX_TOKEN_CONTRACT.callAsync();
+        return ZRXtokenAddress;
+    }
+    private async _invalidateContractInstancesAsync(): Promise<void> {
+        this.unsubscribeAll();
+        delete this._exchangeContractIfExists;
+    }
+    private async _isValidSignatureUsingContractCallAsync(dataHex: string, ecSignature: ECSignature,
+                                                          signerAddressHex: string): Promise<boolean> {
+        assert.isHexString('dataHex', dataHex);
+        assert.doesConformToSchema('ecSignature', ecSignature, schemas.ecSignatureSchema);
+        assert.isETHAddressHex('signerAddressHex', signerAddressHex);
+
+        const exchangeInstance = await this._getExchangeContractAsync();
+
+        const isValidSignature = await exchangeInstance.isValidSignature.callAsync(
+            signerAddressHex,
+            dataHex,
+            ecSignature.v,
+            ecSignature.r,
+            ecSignature.s,
+        );
+        return isValidSignature;
+    }
+    private async _getOrderHashHexUsingContractCallAsync(order: Order|SignedOrder): Promise<string> {
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(order);
+        const orderHashHex = await exchangeInstance.getOrderHash.callAsync(orderAddresses, orderValues);
+        return orderHashHex;
+    }
+    private async _getExchangeContractAsync(): Promise<ExchangeContract> {
+        if (!_.isUndefined(this._exchangeContractIfExists)) {
+            return this._exchangeContractIfExists;
+        }
+        const contractInstance = await this._instantiateContractIfExistsAsync<ExchangeContract>(
+            artifacts.ExchangeArtifact, this._contractAddressIfExists,
+        );
+        this._exchangeContractIfExists = contractInstance as ExchangeContract;
+        return this._exchangeContractIfExists;
+    }
+    private async _getTokenTransferProxyAddressAsync(): Promise<string> {
+        const exchangeInstance = await this._getExchangeContractAsync();
+        const tokenTransferProxyAddress = await exchangeInstance.TOKEN_TRANSFER_PROXY_CONTRACT.callAsync();
+        const tokenTransferProxyAddressLowerCase = tokenTransferProxyAddress.toLowerCase();
+        return tokenTransferProxyAddressLowerCase;
+    }
+}
diff --git a/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts b/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts
new file mode 100644
index 000000000..2cc5a9aa0
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts
@@ -0,0 +1,122 @@
+import * as _ from 'lodash';
+import {Web3Wrapper} from '../web3_wrapper';
+import {assert} from '../utils/assert';
+import {Token, TokenRegistryContract, TokenMetadata} from '../types';
+import {constants} from '../utils/constants';
+import {ContractWrapper} from './contract_wrapper';
+import {artifacts} from '../artifacts';
+
+/**
+ * This class includes all the functionality related to interacting with the 0x Token Registry smart contract.
+ */
+export class TokenRegistryWrapper extends ContractWrapper {
+    private _tokenRegistryContractIfExists?: TokenRegistryContract;
+    private _contractAddressIfExists?: string;
+    constructor(web3Wrapper: Web3Wrapper, contractAddressIfExists?: string) {
+        super(web3Wrapper);
+        this._contractAddressIfExists = contractAddressIfExists;
+    }
+    /**
+     * Retrieves all the tokens currently listed in the Token Registry smart contract
+     * @return  An array of objects that conform to the Token interface.
+     */
+    public async getTokensAsync(): Promise<Token[]> {
+        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
+
+        const addresses = await this.getTokenAddressesAsync();
+        const tokenPromises: Array<Promise<Token|undefined>> = _.map(
+            addresses,
+            (address: string) => (this.getTokenIfExistsAsync(address)),
+        );
+        const tokens = await Promise.all(tokenPromises);
+        return tokens as Token[];
+    }
+    /**
+     * Retrieves all the addresses of the tokens currently listed in the Token Registry smart contract
+     * @return  An array of token addresses.
+     */
+    public async getTokenAddressesAsync(): Promise<string[]> {
+        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
+        const addresses = await tokenRegistryContract.getTokenAddresses.callAsync();
+        return addresses;
+    }
+    /**
+     * Retrieves a token by address currently listed in the Token Registry smart contract
+     * @return  An object that conforms to the Token interface or undefined if token not found.
+     */
+    public async getTokenIfExistsAsync(address: string): Promise<Token|undefined> {
+        assert.isETHAddressHex('address', address);
+
+        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
+        const metadata = await tokenRegistryContract.getTokenMetaData.callAsync(address);
+        const token = this._createTokenFromMetadata(metadata);
+        return token;
+    }
+    public async getTokenAddressBySymbolIfExistsAsync(symbol: string): Promise<string|undefined> {
+        assert.isString('symbol', symbol);
+        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
+        const addressIfExists = await tokenRegistryContract.getTokenAddressBySymbol.callAsync(symbol);
+        if (addressIfExists === constants.NULL_ADDRESS) {
+            return undefined;
+        }
+        return addressIfExists;
+    }
+    public async getTokenAddressByNameIfExistsAsync(name: string): Promise<string|undefined> {
+        assert.isString('name', name);
+        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
+        const addressIfExists = await tokenRegistryContract.getTokenAddressByName.callAsync(name);
+        if (addressIfExists === constants.NULL_ADDRESS) {
+            return undefined;
+        }
+        return addressIfExists;
+    }
+    public async getTokenBySymbolIfExistsAsync(symbol: string): Promise<Token|undefined> {
+        assert.isString('symbol', symbol);
+        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
+        const metadata = await tokenRegistryContract.getTokenBySymbol.callAsync(symbol);
+        const token = this._createTokenFromMetadata(metadata);
+        return token;
+    }
+    public async getTokenByNameIfExistsAsync(name: string): Promise<Token|undefined> {
+        assert.isString('name', name);
+        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
+        const metadata = await tokenRegistryContract.getTokenByName.callAsync(name);
+        const token = this._createTokenFromMetadata(metadata);
+        return token;
+    }
+    /**
+     * Retrieves the Ethereum address of the TokenRegistry contract deployed on the network
+     * that the user-passed web3 provider is connected to.
+     * @returns The Ethereum address of the TokenRegistry contract being used.
+     */
+    public async getContractAddressAsync(): Promise<string> {
+        const tokenRegistryInstance = await this._getTokenRegistryContractAsync();
+        const tokenRegistryAddress = tokenRegistryInstance.address;
+        return tokenRegistryAddress;
+    }
+    private _createTokenFromMetadata(metadata: TokenMetadata): Token|undefined {
+        if (metadata[0] === constants.NULL_ADDRESS) {
+            return undefined;
+        }
+        const token = {
+            address: metadata[0],
+            name: metadata[1],
+            symbol: metadata[2],
+            decimals: metadata[3].toNumber(),
+        };
+        return token;
+    }
+    private _invalidateContractInstance(): void {
+        delete this._tokenRegistryContractIfExists;
+    }
+    private async _getTokenRegistryContractAsync(): Promise<TokenRegistryContract> {
+        if (!_.isUndefined(this._tokenRegistryContractIfExists)) {
+            return this._tokenRegistryContractIfExists;
+        }
+        const contractInstance = await this._instantiateContractIfExistsAsync<TokenRegistryContract>(
+            artifacts.TokenRegistryArtifact, this._contractAddressIfExists,
+        );
+        this._tokenRegistryContractIfExists = contractInstance as TokenRegistryContract;
+        return this._tokenRegistryContractIfExists;
+    }
+}
diff --git a/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts b/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts
new file mode 100644
index 000000000..f81845af9
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts
@@ -0,0 +1,60 @@
+import * as _ from 'lodash';
+import {Web3Wrapper} from '../web3_wrapper';
+import {ContractWrapper} from './contract_wrapper';
+import {artifacts} from '../artifacts';
+import {TokenTransferProxyContract} from '../types';
+
+/**
+ * This class includes the functionality related to interacting with the TokenTransferProxy contract.
+ */
+export class TokenTransferProxyWrapper extends ContractWrapper {
+    private _tokenTransferProxyContractIfExists?: TokenTransferProxyContract;
+    private _tokenTransferProxyContractAddressFetcher: () => Promise<string>;
+    constructor(web3Wrapper: Web3Wrapper, tokenTransferProxyContractAddressFetcher: () => Promise<string>) {
+        super(web3Wrapper);
+        this._tokenTransferProxyContractAddressFetcher = tokenTransferProxyContractAddressFetcher;
+    }
+    /**
+     * Check if the Exchange contract address is authorized by the TokenTransferProxy contract.
+     * @param   exchangeContractAddress     The hex encoded address of the Exchange contract to call.
+     * @return  Whether the exchangeContractAddress is authorized.
+     */
+    public async isAuthorizedAsync(exchangeContractAddress: string): Promise<boolean> {
+        const tokenTransferProxyContractInstance = await this._getTokenTransferProxyContractAsync();
+        const isAuthorized = await tokenTransferProxyContractInstance.authorized.callAsync(exchangeContractAddress);
+        return isAuthorized;
+    }
+    /**
+     * Get the list of all Exchange contract addresses authorized by the TokenTransferProxy contract.
+     * @return  The list of authorized addresses.
+     */
+    public async getAuthorizedAddressesAsync(): Promise<string[]> {
+        const tokenTransferProxyContractInstance = await this._getTokenTransferProxyContractAsync();
+        const authorizedAddresses = await tokenTransferProxyContractInstance.getAuthorizedAddresses.callAsync();
+        return authorizedAddresses;
+    }
+    /**
+     * Retrieves the Ethereum address of the TokenTransferProxy contract deployed on the network
+     * that the user-passed web3 provider is connected to.
+     * @returns The Ethereum address of the TokenTransferProxy contract being used.
+     */
+    public async getContractAddressAsync(): Promise<string> {
+        const proxyInstance = await this._getTokenTransferProxyContractAsync();
+        const proxyAddress = proxyInstance.address;
+        return proxyAddress;
+    }
+    private _invalidateContractInstance(): void {
+        delete this._tokenTransferProxyContractIfExists;
+    }
+    private async _getTokenTransferProxyContractAsync(): Promise<TokenTransferProxyContract> {
+        if (!_.isUndefined(this._tokenTransferProxyContractIfExists)) {
+            return this._tokenTransferProxyContractIfExists;
+        }
+        const contractAddress = await this._tokenTransferProxyContractAddressFetcher();
+        const contractInstance = await this._instantiateContractIfExistsAsync<TokenTransferProxyContract>(
+            artifacts.TokenTransferProxyArtifact, contractAddress,
+        );
+        this._tokenTransferProxyContractIfExists = contractInstance as TokenTransferProxyContract;
+        return this._tokenTransferProxyContractIfExists;
+    }
+}
diff --git a/packages/0x.js/src/contract_wrappers/token_wrapper.ts b/packages/0x.js/src/contract_wrappers/token_wrapper.ts
new file mode 100644
index 000000000..614ac19d4
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/token_wrapper.ts
@@ -0,0 +1,313 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {schemas} from '0x-json-schemas';
+import {Web3Wrapper} from '../web3_wrapper';
+import {assert} from '../utils/assert';
+import {constants} from '../utils/constants';
+import {ContractWrapper} from './contract_wrapper';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {artifacts} from '../artifacts';
+import {
+    TokenContract,
+    ZeroExError,
+    TokenEvents,
+    IndexedFilterValues,
+    SubscriptionOpts,
+    MethodOpts,
+    LogWithDecodedArgs,
+    EventCallback,
+    TokenContractEventArgs,
+} from '../types';
+
+const ALLOWANCE_TO_ZERO_GAS_AMOUNT = 47275;
+
+/**
+ * This class includes all the functionality related to interacting with ERC20 token contracts.
+ * All ERC20 method calls are supported, along with some convenience methods for getting/setting allowances
+ * to the 0x Proxy smart contract.
+ */
+export class TokenWrapper extends ContractWrapper {
+    public UNLIMITED_ALLOWANCE_IN_BASE_UNITS = constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
+    private _tokenContractsByAddress: {[address: string]: TokenContract};
+    private _tokenTransferProxyContractAddressFetcher: () => Promise<string>;
+    constructor(web3Wrapper: Web3Wrapper, abiDecoder: AbiDecoder,
+                tokenTransferProxyContractAddressFetcher: () => Promise<string>) {
+        super(web3Wrapper, abiDecoder);
+        this._tokenContractsByAddress = {};
+        this._tokenTransferProxyContractAddressFetcher = tokenTransferProxyContractAddressFetcher;
+    }
+    /**
+     * Retrieves an owner's ERC20 token balance.
+     * @param   tokenAddress    The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   ownerAddress    The hex encoded user Ethereum address whose balance you would like to check.
+     * @param   methodOpts      Optional arguments this method accepts.
+     * @return  The owner's ERC20 token balance in base units.
+     */
+    public async getBalanceAsync(tokenAddress: string, ownerAddress: string,
+                                 methodOpts?: MethodOpts): Promise<BigNumber> {
+        assert.isETHAddressHex('ownerAddress', ownerAddress);
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+
+        const tokenContract = await this._getTokenContractAsync(tokenAddress);
+        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
+        let balance = await tokenContract.balanceOf.callAsync(ownerAddress, defaultBlock);
+        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
+        balance = new BigNumber(balance);
+        return balance;
+    }
+    /**
+     * Sets the spender's allowance to a specified number of baseUnits on behalf of the owner address.
+     * Equivalent to the ERC20 spec method `approve`.
+     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   ownerAddress        The hex encoded user Ethereum address who would like to set an allowance
+     *                              for spenderAddress.
+     * @param   spenderAddress      The hex encoded user Ethereum address who will be able to spend the set allowance.
+     * @param   amountInBaseUnits   The allowance amount you would like to set.
+     * @return Transaction hash.
+     */
+    public async setAllowanceAsync(tokenAddress: string, ownerAddress: string, spenderAddress: string,
+                                   amountInBaseUnits: BigNumber): Promise<string> {
+        await assert.isSenderAddressAsync('ownerAddress', ownerAddress, this._web3Wrapper);
+        assert.isETHAddressHex('spenderAddress', spenderAddress);
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
+
+        const tokenContract = await this._getTokenContractAsync(tokenAddress);
+        // Hack: for some reason default estimated gas amount causes `base fee exceeds gas limit` exception
+        // on testrpc. Probably related to https://github.com/ethereumjs/testrpc/issues/294
+        // TODO: Debug issue in testrpc and submit a PR, then remove this hack
+        const networkIdIfExists = await this._web3Wrapper.getNetworkIdIfExistsAsync();
+        const gas = networkIdIfExists === constants.TESTRPC_NETWORK_ID ? ALLOWANCE_TO_ZERO_GAS_AMOUNT : undefined;
+        const txHash = await tokenContract.approve.sendTransactionAsync(spenderAddress, amountInBaseUnits, {
+            from: ownerAddress,
+            gas,
+        });
+        return txHash;
+    }
+    /**
+     * Sets the spender's allowance to an unlimited number of baseUnits on behalf of the owner address.
+     * Equivalent to the ERC20 spec method `approve`.
+     * Setting an unlimited allowance will lower the gas cost for filling orders involving tokens that forego updating
+     * allowances set to the max amount (e.g ZRX, WETH)
+     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   ownerAddress        The hex encoded user Ethereum address who would like to set an allowance
+     *                              for spenderAddress.
+     * @param   spenderAddress      The hex encoded user Ethereum address who will be able to spend the set allowance.
+     * @return Transaction hash.
+     */
+    public async setUnlimitedAllowanceAsync(tokenAddress: string, ownerAddress: string,
+                                            spenderAddress: string): Promise<string> {
+        const txHash = await this.setAllowanceAsync(
+            tokenAddress, ownerAddress, spenderAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+        );
+        return txHash;
+    }
+    /**
+     * Retrieves the owners allowance in baseUnits set to the spender's address.
+     * @param   tokenAddress    The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   ownerAddress    The hex encoded user Ethereum address whose allowance to spenderAddress
+     *                          you would like to retrieve.
+     * @param   spenderAddress  The hex encoded user Ethereum address who can spend the allowance you are fetching.
+     * @param   methodOpts      Optional arguments this method accepts.
+     */
+    public async getAllowanceAsync(tokenAddress: string, ownerAddress: string,
+                                   spenderAddress: string, methodOpts?: MethodOpts): Promise<BigNumber> {
+        assert.isETHAddressHex('ownerAddress', ownerAddress);
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+
+        const tokenContract = await this._getTokenContractAsync(tokenAddress);
+        const defaultBlock = _.isUndefined(methodOpts) ? undefined : methodOpts.defaultBlock;
+        let allowanceInBaseUnits = await tokenContract.allowance.callAsync(ownerAddress, spenderAddress, defaultBlock);
+        // Wrap BigNumbers returned from web3 with our own (later) version of BigNumber
+        allowanceInBaseUnits = new BigNumber(allowanceInBaseUnits);
+        return allowanceInBaseUnits;
+    }
+    /**
+     * Retrieves the owner's allowance in baseUnits set to the 0x proxy contract.
+     * @param   tokenAddress    The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   ownerAddress    The hex encoded user Ethereum address whose proxy contract allowance we are retrieving.
+     * @param   methodOpts      Optional arguments this method accepts.
+     */
+    public async getProxyAllowanceAsync(tokenAddress: string, ownerAddress: string,
+                                        methodOpts?: MethodOpts): Promise<BigNumber> {
+        assert.isETHAddressHex('ownerAddress', ownerAddress);
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+
+        const proxyAddress = await this._getTokenTransferProxyAddressAsync();
+        const allowanceInBaseUnits = await this.getAllowanceAsync(tokenAddress, ownerAddress, proxyAddress, methodOpts);
+        return allowanceInBaseUnits;
+    }
+    /**
+     * Sets the 0x proxy contract's allowance to a specified number of a tokens' baseUnits on behalf
+     * of an owner address.
+     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   ownerAddress        The hex encoded user Ethereum address who is setting an allowance
+     *                              for the Proxy contract.
+     * @param   amountInBaseUnits   The allowance amount specified in baseUnits.
+     * @return Transaction hash.
+     */
+    public async setProxyAllowanceAsync(tokenAddress: string, ownerAddress: string,
+                                        amountInBaseUnits: BigNumber): Promise<string> {
+        assert.isETHAddressHex('ownerAddress', ownerAddress);
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
+
+        const proxyAddress = await this._getTokenTransferProxyAddressAsync();
+        const txHash = await this.setAllowanceAsync(tokenAddress, ownerAddress, proxyAddress, amountInBaseUnits);
+        return txHash;
+    }
+    /**
+     * Sets the 0x proxy contract's allowance to a unlimited number of a tokens' baseUnits on behalf
+     * of an owner address.
+     * Setting an unlimited allowance will lower the gas cost for filling orders involving tokens that forego updating
+     * allowances set to the max amount (e.g ZRX, WETH)
+     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   ownerAddress        The hex encoded user Ethereum address who is setting an allowance
+     *                              for the Proxy contract.
+     * @return Transaction hash.
+     */
+    public async setUnlimitedProxyAllowanceAsync(tokenAddress: string, ownerAddress: string): Promise<string> {
+        const txHash = await this.setProxyAllowanceAsync(
+            tokenAddress, ownerAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+        );
+        return txHash;
+    }
+    /**
+     * Transfers `amountInBaseUnits` ERC20 tokens from `fromAddress` to `toAddress`.
+     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   fromAddress         The hex encoded user Ethereum address that will send the funds.
+     * @param   toAddress           The hex encoded user Ethereum address that will receive the funds.
+     * @param   amountInBaseUnits   The amount (specified in baseUnits) of the token to transfer.
+     * @return Transaction hash.
+     */
+    public async transferAsync(tokenAddress: string, fromAddress: string, toAddress: string,
+                               amountInBaseUnits: BigNumber): Promise<string> {
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+        await assert.isSenderAddressAsync('fromAddress', fromAddress, this._web3Wrapper);
+        assert.isETHAddressHex('toAddress', toAddress);
+        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
+
+        const tokenContract = await this._getTokenContractAsync(tokenAddress);
+
+        const fromAddressBalance = await this.getBalanceAsync(tokenAddress, fromAddress);
+        if (fromAddressBalance.lessThan(amountInBaseUnits)) {
+            throw new Error(ZeroExError.InsufficientBalanceForTransfer);
+        }
+
+        const txHash = await tokenContract.transfer.sendTransactionAsync(toAddress, amountInBaseUnits, {
+            from: fromAddress,
+        });
+        return txHash;
+    }
+    /**
+     * Transfers `amountInBaseUnits` ERC20 tokens from `fromAddress` to `toAddress`.
+     * Requires the fromAddress to have sufficient funds and to have approved an allowance of
+     * `amountInBaseUnits` to `senderAddress`.
+     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
+     * @param   fromAddress         The hex encoded user Ethereum address whose funds are being sent.
+     * @param   toAddress           The hex encoded user Ethereum address that will receive the funds.
+     * @param   senderAddress       The hex encoded user Ethereum address whose initiates the fund transfer. The
+     *                              `fromAddress` must have set an allowance to the `senderAddress`
+     *                              before this call.
+     * @param   amountInBaseUnits   The amount (specified in baseUnits) of the token to transfer.
+     * @return Transaction hash.
+     */
+    public async transferFromAsync(tokenAddress: string, fromAddress: string, toAddress: string,
+                                   senderAddress: string, amountInBaseUnits: BigNumber):
+                                   Promise<string> {
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+        assert.isETHAddressHex('fromAddress', fromAddress);
+        assert.isETHAddressHex('toAddress', toAddress);
+        await assert.isSenderAddressAsync('senderAddress', senderAddress, this._web3Wrapper);
+        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);
+
+        const tokenContract = await this._getTokenContractAsync(tokenAddress);
+
+        const fromAddressAllowance = await this.getAllowanceAsync(tokenAddress, fromAddress, senderAddress);
+        if (fromAddressAllowance.lessThan(amountInBaseUnits)) {
+            throw new Error(ZeroExError.InsufficientAllowanceForTransfer);
+        }
+
+        const fromAddressBalance = await this.getBalanceAsync(tokenAddress, fromAddress);
+        if (fromAddressBalance.lessThan(amountInBaseUnits)) {
+            throw new Error(ZeroExError.InsufficientBalanceForTransfer);
+        }
+
+        const txHash = await tokenContract.transferFrom.sendTransactionAsync(
+            fromAddress, toAddress, amountInBaseUnits,
+            {
+                from: senderAddress,
+            },
+        );
+        return txHash;
+    }
+    /**
+     * Subscribe to an event type emitted by the Token contract.
+     * @param   tokenAddress        The hex encoded address where the ERC20 token is deployed.
+     * @param   eventName           The token contract event you would like to subscribe to.
+     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
+     *                              the value is the value you are interested in. E.g `{maker: aUserAddressHex}`
+     * @param   callback            Callback that gets called when a log is added/removed
+     * @return Subscription token used later to unsubscribe
+     */
+    public subscribe<ArgsType extends TokenContractEventArgs>(
+        tokenAddress: string, eventName: TokenEvents, indexFilterValues: IndexedFilterValues,
+        callback: EventCallback<ArgsType>): string {
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+        assert.doesBelongToStringEnum('eventName', eventName, TokenEvents);
+        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
+        assert.isFunction('callback', callback);
+        const subscriptionToken = this._subscribe<ArgsType>(
+            tokenAddress, eventName, indexFilterValues, artifacts.TokenArtifact.abi, callback,
+        );
+        return subscriptionToken;
+    }
+    /**
+     * Cancel a subscription
+     * @param   subscriptionToken Subscription token returned by `subscribe()`
+     */
+    public unsubscribe(subscriptionToken: string): void {
+        this._unsubscribe(subscriptionToken);
+    }
+    /**
+     * Gets historical logs without creating a subscription
+     * @param   tokenAddress        An address of the token that emmited the logs.
+     * @param   eventName           The token contract event you would like to subscribe to.
+     * @param   subscriptionOpts    Subscriptions options that let you configure the subscription.
+     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
+     *                              the value is the value you are interested in. E.g `{_from: aUserAddressHex}`
+     * @return  Array of logs that match the parameters
+     */
+    public async getLogsAsync<ArgsType extends TokenContractEventArgs>(
+        tokenAddress: string, eventName: TokenEvents, subscriptionOpts: SubscriptionOpts,
+        indexFilterValues: IndexedFilterValues): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
+        assert.isETHAddressHex('tokenAddress', tokenAddress);
+        assert.doesBelongToStringEnum('eventName', eventName, TokenEvents);
+        assert.doesConformToSchema('subscriptionOpts', subscriptionOpts, schemas.subscriptionOptsSchema);
+        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
+        const logs = await this._getLogsAsync<ArgsType>(
+            tokenAddress, eventName, subscriptionOpts, indexFilterValues, artifacts.TokenArtifact.abi,
+        );
+        return logs;
+    }
+    private _invalidateContractInstancesAsync(): void {
+        this.unsubscribeAll();
+        this._tokenContractsByAddress = {};
+    }
+    private async _getTokenContractAsync(tokenAddress: string): Promise<TokenContract> {
+        let tokenContract = this._tokenContractsByAddress[tokenAddress];
+        if (!_.isUndefined(tokenContract)) {
+            return tokenContract;
+        }
+        const contractInstance = await this._instantiateContractIfExistsAsync<TokenContract>(
+            artifacts.TokenArtifact, tokenAddress,
+        );
+        tokenContract = contractInstance as TokenContract;
+        this._tokenContractsByAddress[tokenAddress] = tokenContract;
+        return tokenContract;
+    }
+    private async _getTokenTransferProxyAddressAsync(): Promise<string> {
+        const tokenTransferProxyContractAddress = await this._tokenTransferProxyContractAddressFetcher();
+        return tokenTransferProxyContractAddress;
+    }
+}
diff --git a/packages/0x.js/src/globals.d.ts b/packages/0x.js/src/globals.d.ts
new file mode 100644
index 000000000..cb3800056
--- /dev/null
+++ b/packages/0x.js/src/globals.d.ts
@@ -0,0 +1,80 @@
+/// <reference types='chai-typescript-typings' />
+/// <reference types='chai-as-promised-typescript-typings' />
+declare module 'web3_beta';
+declare module 'chai-bignumber';
+declare module 'dirty-chai';
+declare module 'request-promise-native';
+declare module 'web3-provider-engine';
+declare module 'web3-provider-engine/subproviders/rpc';
+
+// HACK: In order to merge the bignumber declaration added by chai-bignumber to the chai Assertion
+// interface we must use `namespace` as the Chai definitelyTyped definition does. Since we otherwise
+// disallow `namespace`, we disable tslint for the following.
+/* tslint:disable */
+declare namespace Chai {
+    interface Assertion {
+        bignumber: Assertion;
+        // HACK: In order to comply with chai-as-promised we make eventually a `PromisedAssertion` not an `Assertion`
+        eventually: PromisedAssertion;
+    }
+}
+/* tslint:enable */
+
+declare module '*.json' {
+    const json: any;
+    /* tslint:disable */
+    export default json;
+    /* tslint:enable */
+}
+
+// find-version declarations
+declare function findVersions(version: string): string[];
+declare module 'find-versions' {
+    export = findVersions;
+}
+
+// compare-version declarations
+declare function compareVersions(firstVersion: string, secondVersion: string): number;
+declare module 'compare-versions' {
+    export = compareVersions;
+}
+
+// es6-promisify declarations
+declare function promisify(original: any, settings?: any): ((...arg: any[]) => Promise<any>);
+declare module 'es6-promisify' {
+    export = promisify;
+}
+
+declare module 'ethereumjs-abi' {
+    const soliditySHA3: (argTypes: string[], args: any[]) => Buffer;
+}
+
+// truffle-hdwallet-provider declarations
+declare module 'truffle-hdwallet-provider' {
+    import * as Web3 from 'web3';
+    class HDWalletProvider implements Web3.Provider {
+        constructor(mnemonic: string, rpcUrl: string);
+        public sendAsync(
+            payload: Web3.JSONRPCRequestPayload,
+            callback: (err: Error, result: Web3.JSONRPCResponsePayload) => void,
+        ): void;
+    }
+    export = HDWalletProvider;
+}
+
+// abi-decoder declarations
+interface DecodedLogArg {
+}
+interface DecodedLog {
+    name: string;
+    events: DecodedLogArg[];
+}
+declare module 'abi-decoder' {
+    import * as Web3 from 'web3';
+    const addABI: (abi: Web3.AbiDefinition) => void;
+    const decodeLogs: (logs: Web3.LogEntry[]) => DecodedLog[];
+}
+
+declare module 'web3/lib/solidity/coder' {
+    const decodeParams: (types: string[], data: string) => any[];
+}
diff --git a/packages/0x.js/src/globalsAugment.d.ts b/packages/0x.js/src/globalsAugment.d.ts
new file mode 100644
index 000000000..60e2312a3
--- /dev/null
+++ b/packages/0x.js/src/globalsAugment.d.ts
@@ -0,0 +1,23 @@
+import BigNumber from 'bignumber.js';
+
+// HACK: This module overrides the Chai namespace so that we can use BigNumber types inside.
+// Source: https://github.com/Microsoft/TypeScript/issues/7352#issuecomment-191547232
+declare global {
+    // HACK: In order to merge the bignumber declaration added by chai-bignumber to the chai Assertion
+    // interface we must use `namespace` as the Chai definitelyTyped definition does. Since we otherwise
+    // disallow `namespace`, we disable tslint for the following.
+    /* tslint:disable */
+    namespace Chai {
+        interface NumberComparer {
+            (value: number|BigNumber, message?: string): Assertion;
+        }
+        interface NumericComparison {
+            greaterThan: NumberComparer;
+        }
+    }
+    /* tslint:enable */
+    interface DecodedLogArg {
+        name: string;
+        value: string|BigNumber;
+    }
+}
diff --git a/packages/0x.js/src/index.ts b/packages/0x.js/src/index.ts
new file mode 100644
index 000000000..1b3e893ba
--- /dev/null
+++ b/packages/0x.js/src/index.ts
@@ -0,0 +1,45 @@
+export {ZeroEx} from './0x';
+
+export {
+    Order,
+    SignedOrder,
+    ECSignature,
+    ZeroExError,
+    EventCallback,
+    EventCallbackAsync,
+    EventCallbackSync,
+    ExchangeContractErrs,
+    ContractEvent,
+    Token,
+    ExchangeEvents,
+    TokenEvents,
+    IndexedFilterValues,
+    SubscriptionOpts,
+    BlockParam,
+    OrderCancellationRequest,
+    OrderFillRequest,
+    LogErrorContractEventArgs,
+    LogCancelContractEventArgs,
+    LogFillContractEventArgs,
+    ExchangeContractEventArgs,
+    TransferContractEventArgs,
+    ApprovalContractEventArgs,
+    TokenContractEventArgs,
+    ContractEventArgs,
+    ContractEventArg,
+    Web3Provider,
+    ZeroExConfig,
+    TransactionReceipt,
+    TransactionReceiptWithDecodedLogs,
+    LogWithDecodedArgs,
+    MethodOpts,
+    OrderTransactionOpts,
+    FilterObject,
+    LogEvent,
+    DecodedLogEvent,
+    EventWatcherCallback,
+    OnOrderStateChangeCallback,
+    OrderStateValid,
+    OrderStateInvalid,
+    OrderState,
+} from './types';
diff --git a/packages/0x.js/src/order_watcher/event_watcher.ts b/packages/0x.js/src/order_watcher/event_watcher.ts
new file mode 100644
index 000000000..81529a98c
--- /dev/null
+++ b/packages/0x.js/src/order_watcher/event_watcher.ts
@@ -0,0 +1,88 @@
+import * as Web3 from 'web3';
+import * as _ from 'lodash';
+import {Web3Wrapper} from '../web3_wrapper';
+import {
+    BlockParamLiteral,
+    EventCallback,
+    EventWatcherCallback,
+    ZeroExError,
+} from '../types';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {intervalUtils} from '../utils/interval_utils';
+import {assert} from '../utils/assert';
+import {utils} from '../utils/utils';
+
+const DEFAULT_EVENT_POLLING_INTERVAL = 200;
+
+enum LogEventState {
+    Removed,
+    Added,
+}
+
+/*
+ * The EventWatcher watches for blockchain events at the specified block confirmation
+ * depth.
+ */
+export class EventWatcher {
+    private _web3Wrapper: Web3Wrapper;
+    private _pollingIntervalMs: number;
+    private _intervalIdIfExists?: NodeJS.Timer;
+    private _lastEvents: Web3.LogEntry[] = [];
+    constructor(web3Wrapper: Web3Wrapper, pollingIntervalMs: undefined|number) {
+        this._web3Wrapper = web3Wrapper;
+        this._pollingIntervalMs = _.isUndefined(pollingIntervalMs) ?
+                                    DEFAULT_EVENT_POLLING_INTERVAL :
+                                    pollingIntervalMs;
+    }
+    public subscribe(callback: EventWatcherCallback): void {
+        assert.isFunction('callback', callback);
+        if (!_.isUndefined(this._intervalIdIfExists)) {
+            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
+        }
+        this._intervalIdIfExists = intervalUtils.setAsyncExcludingInterval(
+            this._pollForBlockchainEventsAsync.bind(this, callback), this._pollingIntervalMs,
+        );
+    }
+    public unsubscribe(): void {
+        this._lastEvents = [];
+        if (!_.isUndefined(this._intervalIdIfExists)) {
+            intervalUtils.clearAsyncExcludingInterval(this._intervalIdIfExists);
+            delete this._intervalIdIfExists;
+        }
+    }
+    private async _pollForBlockchainEventsAsync(callback: EventWatcherCallback): Promise<void> {
+        const pendingEvents = await this._getEventsAsync();
+        if (pendingEvents.length === 0) {
+            // HACK: Sometimes when node rebuilds the pending block we get back the empty result.
+            // We don't want to emit a lot of removal events and bring them back after a couple of miliseconds,
+            // that's why we just ignore those cases.
+            return;
+        }
+        const removedEvents = _.differenceBy(this._lastEvents, pendingEvents, JSON.stringify);
+        const newEvents = _.differenceBy(pendingEvents, this._lastEvents, JSON.stringify);
+        await this._emitDifferencesAsync(removedEvents, LogEventState.Removed, callback);
+        await this._emitDifferencesAsync(newEvents, LogEventState.Added, callback);
+        this._lastEvents = pendingEvents;
+    }
+    private async _getEventsAsync(): Promise<Web3.LogEntry[]> {
+        const eventFilter = {
+            fromBlock: BlockParamLiteral.Pending,
+            toBlock: BlockParamLiteral.Pending,
+        };
+        const events = await this._web3Wrapper.getLogsAsync(eventFilter);
+        return events;
+    }
+    private async _emitDifferencesAsync(
+        logs: Web3.LogEntry[], logEventState: LogEventState, callback: EventWatcherCallback,
+    ): Promise<void> {
+        for (const log of logs) {
+            const logEvent = {
+                removed: logEventState === LogEventState.Removed,
+                ...log,
+            };
+            if (!_.isUndefined(this._intervalIdIfExists)) {
+                await callback(logEvent);
+            }
+        }
+    }
+}
diff --git a/packages/0x.js/src/order_watcher/order_state_watcher.ts b/packages/0x.js/src/order_watcher/order_state_watcher.ts
new file mode 100644
index 000000000..139f13fdf
--- /dev/null
+++ b/packages/0x.js/src/order_watcher/order_state_watcher.ts
@@ -0,0 +1,232 @@
+import * as _ from 'lodash';
+import {schemas} from '0x-json-schemas';
+import {ZeroEx} from '../0x';
+import {EventWatcher} from './event_watcher';
+import {assert} from '../utils/assert';
+import {utils} from '../utils/utils';
+import {artifacts} from '../artifacts';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {OrderStateUtils} from '../utils/order_state_utils';
+import {
+    LogEvent,
+    OrderState,
+    SignedOrder,
+    Web3Provider,
+    BlockParamLiteral,
+    LogWithDecodedArgs,
+    ContractEventArgs,
+    OnOrderStateChangeCallback,
+    OrderStateWatcherConfig,
+    ApprovalContractEventArgs,
+    TransferContractEventArgs,
+    LogFillContractEventArgs,
+    LogCancelContractEventArgs,
+    ExchangeEvents,
+    TokenEvents,
+    ZeroExError,
+} from '../types';
+import {Web3Wrapper} from '../web3_wrapper';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
+import {OrderFilledCancelledLazyStore} from '../stores/order_filled_cancelled_lazy_store';
+import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+
+const DEFAULT_NUM_CONFIRMATIONS = 0;
+
+interface DependentOrderHashes {
+    [makerAddress: string]: {
+        [makerToken: string]: Set<string>,
+    };
+}
+
+interface OrderByOrderHash {
+    [orderHash: string]: SignedOrder;
+}
+
+/**
+ * This class includes all the functionality related to watching a set of orders
+ * for potential changes in order validity/fillability. The orderWatcher notifies
+ * the subscriber of these changes so that a final decison can be made on whether
+ * the order should be deemed invalid.
+ */
+export class OrderStateWatcher {
+    private _orderByOrderHash: OrderByOrderHash = {};
+    private _dependentOrderHashes: DependentOrderHashes = {};
+    private _callbackIfExistsAsync?: OnOrderStateChangeCallback;
+    private _eventWatcher: EventWatcher;
+    private _web3Wrapper: Web3Wrapper;
+    private _abiDecoder: AbiDecoder;
+    private _orderStateUtils: OrderStateUtils;
+    private _orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore;
+    private _balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore;
+    constructor(
+        web3Wrapper: Web3Wrapper, abiDecoder: AbiDecoder, token: TokenWrapper, exchange: ExchangeWrapper,
+        config?: OrderStateWatcherConfig,
+    ) {
+        this._abiDecoder = abiDecoder;
+        this._web3Wrapper = web3Wrapper;
+        const eventPollingIntervalMs = _.isUndefined(config) ? undefined : config.eventPollingIntervalMs;
+        this._eventWatcher = new EventWatcher(web3Wrapper, eventPollingIntervalMs);
+        this._balanceAndProxyAllowanceLazyStore = new BalanceAndProxyAllowanceLazyStore(token);
+        this._orderFilledCancelledLazyStore = new OrderFilledCancelledLazyStore(exchange);
+        this._orderStateUtils = new OrderStateUtils(
+            this._balanceAndProxyAllowanceLazyStore, this._orderFilledCancelledLazyStore,
+        );
+    }
+    /**
+     * Add an order to the orderStateWatcher. Before the order is added, it's
+     * signature is verified.
+     * @param   signedOrder     The order you wish to start watching.
+     */
+    public addOrder(signedOrder: SignedOrder): void {
+        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
+        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        assert.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker);
+        this._orderByOrderHash[orderHash] = signedOrder;
+        this.addToDependentOrderHashes(signedOrder, orderHash);
+    }
+    /**
+     * Removes an order from the orderStateWatcher
+     * @param   orderHash     The orderHash of the order you wish to stop watching.
+     */
+    public removeOrder(orderHash: string): void {
+        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
+        const signedOrder = this._orderByOrderHash[orderHash];
+        if (_.isUndefined(signedOrder)) {
+            return; // noop
+        }
+        delete this._orderByOrderHash[orderHash];
+        this.removeFromDependentOrderHashes(signedOrder.maker, signedOrder.makerTokenAddress, orderHash);
+    }
+    /**
+     * Starts an orderStateWatcher subscription. The callback will be called every time a watched order's
+     * backing blockchain state has changed. This is a call-to-action for the caller to re-validate the order.
+     * @param   callback            Receives the orderHash of the order that should be re-validated, together
+     *                              with all the order-relevant blockchain state needed to re-validate the order.
+     */
+    public subscribe(callback: OnOrderStateChangeCallback): void {
+        assert.isFunction('callback', callback);
+        if (!_.isUndefined(this._callbackIfExistsAsync)) {
+            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
+        }
+        this._callbackIfExistsAsync = callback;
+        this._eventWatcher.subscribe(this._onEventWatcherCallbackAsync.bind(this));
+    }
+    /**
+     * Ends an orderStateWatcher subscription.
+     */
+    public unsubscribe(): void {
+        if (_.isUndefined(this._callbackIfExistsAsync)) {
+            throw new Error(ZeroExError.SubscriptionNotFound);
+        }
+        this._balanceAndProxyAllowanceLazyStore.deleteAll();
+        this._orderFilledCancelledLazyStore.deleteAll();
+        delete this._callbackIfExistsAsync;
+        this._eventWatcher.unsubscribe();
+    }
+    private async _onEventWatcherCallbackAsync(log: LogEvent): Promise<void> {
+        const maybeDecodedLog = this._abiDecoder.tryToDecodeLogOrNoop(log);
+        const isLogDecoded = !_.isUndefined((maybeDecodedLog as LogWithDecodedArgs<any>).event);
+        if (!isLogDecoded) {
+            return; // noop
+        }
+        const decodedLog = maybeDecodedLog as LogWithDecodedArgs<ContractEventArgs>;
+        let makerToken: string;
+        let makerAddress: string;
+        let orderHashesSet: Set<string>;
+        switch (decodedLog.event) {
+            case TokenEvents.Approval:
+            {
+                // Invalidate cache
+                const args = decodedLog.args as ApprovalContractEventArgs;
+                this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(decodedLog.address, args._owner);
+                // Revalidate orders
+                makerToken = decodedLog.address;
+                makerAddress = args._owner;
+                orderHashesSet = _.get(this._dependentOrderHashes, [makerAddress, makerToken]);
+                if (!_.isUndefined(orderHashesSet)) {
+                    const orderHashes = Array.from(orderHashesSet);
+                    await this._emitRevalidateOrdersAsync(orderHashes);
+                }
+                break;
+            }
+            case TokenEvents.Transfer:
+            {
+                // Invalidate cache
+                const args = decodedLog.args as TransferContractEventArgs;
+                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._from);
+                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._to);
+                // Revalidate orders
+                makerToken = decodedLog.address;
+                makerAddress = args._from;
+                orderHashesSet = _.get(this._dependentOrderHashes, [makerAddress, makerToken]);
+                if (!_.isUndefined(orderHashesSet)) {
+                    const orderHashes = Array.from(orderHashesSet);
+                    await this._emitRevalidateOrdersAsync(orderHashes);
+                }
+                break;
+            }
+            case ExchangeEvents.LogFill:
+            {
+                // Invalidate cache
+                const args = decodedLog.args as LogFillContractEventArgs;
+                this._orderFilledCancelledLazyStore.deleteFilledTakerAmount(args.orderHash);
+                // Revalidate orders
+                const orderHash = args.orderHash;
+                const isOrderWatched = !_.isUndefined(this._orderByOrderHash[orderHash]);
+                if (isOrderWatched) {
+                    await this._emitRevalidateOrdersAsync([orderHash]);
+                }
+                break;
+            }
+            case ExchangeEvents.LogCancel:
+            {
+                // Invalidate cache
+                const args = decodedLog.args as LogCancelContractEventArgs;
+                this._orderFilledCancelledLazyStore.deleteCancelledTakerAmount(args.orderHash);
+                // Revalidate orders
+                const orderHash = args.orderHash;
+                const isOrderWatched = !_.isUndefined(this._orderByOrderHash[orderHash]);
+                if (isOrderWatched) {
+                    await this._emitRevalidateOrdersAsync([orderHash]);
+                }
+                break;
+            }
+            case ExchangeEvents.LogError:
+                return; // noop
+
+            default:
+                throw utils.spawnSwitchErr('decodedLog.event', decodedLog.event);
+        }
+    }
+    private async _emitRevalidateOrdersAsync(orderHashes: string[]): Promise<void> {
+        for (const orderHash of orderHashes) {
+            const signedOrder = this._orderByOrderHash[orderHash] as SignedOrder;
+            // Most of these calls will never reach the network because the data is fetched from stores
+            // and only updated when cache is invalidated
+            const orderState = await this._orderStateUtils.getOrderStateAsync(signedOrder);
+            if (_.isUndefined(this._callbackIfExistsAsync)) {
+                break; // Unsubscribe was called
+            }
+            await this._callbackIfExistsAsync(orderState);
+        }
+    }
+    private addToDependentOrderHashes(signedOrder: SignedOrder, orderHash: string) {
+        if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker])) {
+            this._dependentOrderHashes[signedOrder.maker] = {};
+        }
+        if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress])) {
+            this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress] = new Set();
+        }
+        this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress].add(orderHash);
+    }
+    private removeFromDependentOrderHashes(makerAddress: string, makerTokenAddress: string, orderHash: string) {
+        this._dependentOrderHashes[makerAddress][makerTokenAddress].delete(orderHash);
+        if (this._dependentOrderHashes[makerAddress][makerTokenAddress].size === 0) {
+            delete this._dependentOrderHashes[makerAddress][makerTokenAddress];
+        }
+        if (_.isEmpty(this._dependentOrderHashes[makerAddress])) {
+            delete this._dependentOrderHashes[makerAddress];
+        }
+    }
+}
diff --git a/packages/0x.js/src/schemas/zero_ex_config_schema.ts b/packages/0x.js/src/schemas/zero_ex_config_schema.ts
new file mode 100644
index 000000000..6d4b3ed27
--- /dev/null
+++ b/packages/0x.js/src/schemas/zero_ex_config_schema.ts
@@ -0,0 +1,23 @@
+export const zeroExConfigSchema = {
+    id: '/ZeroExConfig',
+    properties: {
+        gasPrice: {$ref: '/Number'},
+        exchangeContractAddress: {$ref: '/Address'},
+        tokenRegistryContractAddress: {$ref: '/Address'},
+        etherTokenContractAddress: {$ref: '/Address'},
+        orderWatcherConfig: {
+            type: 'object',
+            properties: {
+                pollingIntervalMs: {
+                    type: 'number',
+                    minimum: 0,
+                },
+                numConfirmations: {
+                    type: 'number',
+                    minimum: 0,
+                },
+            },
+        },
+    },
+    type: 'object',
+};
diff --git a/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts b/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts
new file mode 100644
index 000000000..c83e61606
--- /dev/null
+++ b/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts
@@ -0,0 +1,82 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import {BigNumber} from 'bignumber.js';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {BlockParamLiteral} from '../types';
+
+/**
+ * Copy on read store for balances/proxyAllowances of tokens/accounts
+ */
+export class BalanceAndProxyAllowanceLazyStore {
+    private token: TokenWrapper;
+    private balance: {
+        [tokenAddress: string]: {
+            [userAddress: string]: BigNumber,
+        },
+    };
+    private proxyAllowance: {
+        [tokenAddress: string]: {
+            [userAddress: string]: BigNumber,
+        },
+    };
+    constructor(token: TokenWrapper) {
+        this.token = token;
+        this.balance = {};
+        this.proxyAllowance = {};
+    }
+    public async getBalanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber> {
+        if (_.isUndefined(this.balance[tokenAddress]) || _.isUndefined(this.balance[tokenAddress][userAddress])) {
+            const methodOpts = {
+                defaultBlock: BlockParamLiteral.Pending,
+            };
+            const balance = await this.token.getBalanceAsync(tokenAddress, userAddress, methodOpts);
+            this.setBalance(tokenAddress, userAddress, balance);
+        }
+        const cachedBalance = this.balance[tokenAddress][userAddress];
+        return cachedBalance;
+    }
+    public setBalance(tokenAddress: string, userAddress: string, balance: BigNumber): void {
+        if (_.isUndefined(this.balance[tokenAddress])) {
+            this.balance[tokenAddress] = {};
+        }
+        this.balance[tokenAddress][userAddress] = balance;
+    }
+    public deleteBalance(tokenAddress: string, userAddress: string): void {
+        if (!_.isUndefined(this.balance[tokenAddress])) {
+            delete this.balance[tokenAddress][userAddress];
+            if (_.isEmpty(this.balance[tokenAddress])) {
+                delete this.balance[tokenAddress];
+            }
+        }
+    }
+    public async getProxyAllowanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber> {
+        if (_.isUndefined(this.proxyAllowance[tokenAddress]) ||
+            _.isUndefined(this.proxyAllowance[tokenAddress][userAddress])) {
+            const methodOpts = {
+                defaultBlock: BlockParamLiteral.Pending,
+            };
+            const proxyAllowance = await this.token.getProxyAllowanceAsync(tokenAddress, userAddress, methodOpts);
+            this.setProxyAllowance(tokenAddress, userAddress, proxyAllowance);
+        }
+        const cachedProxyAllowance = this.proxyAllowance[tokenAddress][userAddress];
+        return cachedProxyAllowance;
+    }
+    public setProxyAllowance(tokenAddress: string, userAddress: string, proxyAllowance: BigNumber): void {
+        if (_.isUndefined(this.proxyAllowance[tokenAddress])) {
+            this.proxyAllowance[tokenAddress] = {};
+        }
+        this.proxyAllowance[tokenAddress][userAddress] = proxyAllowance;
+    }
+    public deleteProxyAllowance(tokenAddress: string, userAddress: string): void {
+        if (!_.isUndefined(this.proxyAllowance[tokenAddress])) {
+            delete this.proxyAllowance[tokenAddress][userAddress];
+            if (_.isEmpty(this.proxyAllowance[tokenAddress])) {
+                delete this.proxyAllowance[tokenAddress];
+            }
+        }
+    }
+    public deleteAll(): void {
+        this.balance = {};
+        this.proxyAllowance = {};
+    }
+}
diff --git a/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts b/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts
new file mode 100644
index 000000000..9d74da096
--- /dev/null
+++ b/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts
@@ -0,0 +1,61 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import {BigNumber} from 'bignumber.js';
+import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
+import {BlockParamLiteral} from '../types';
+
+/**
+ * Copy on read store for filled/cancelled taker amounts
+ */
+export class OrderFilledCancelledLazyStore {
+    private exchange: ExchangeWrapper;
+    private filledTakerAmount: {
+        [orderHash: string]: BigNumber,
+    };
+    private cancelledTakerAmount: {
+        [orderHash: string]: BigNumber,
+    };
+    constructor(exchange: ExchangeWrapper) {
+        this.exchange = exchange;
+        this.filledTakerAmount = {};
+        this.cancelledTakerAmount = {};
+    }
+    public async getFilledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
+        if (_.isUndefined(this.filledTakerAmount[orderHash])) {
+            const methodOpts = {
+                defaultBlock: BlockParamLiteral.Pending,
+            };
+            const filledTakerAmount = await this.exchange.getFilledTakerAmountAsync(orderHash, methodOpts);
+            this.setFilledTakerAmount(orderHash, filledTakerAmount);
+        }
+        const cachedFilled = this.filledTakerAmount[orderHash];
+        return cachedFilled;
+    }
+    public setFilledTakerAmount(orderHash: string, filledTakerAmount: BigNumber): void {
+        this.filledTakerAmount[orderHash] = filledTakerAmount;
+    }
+    public deleteFilledTakerAmount(orderHash: string): void {
+        delete this.filledTakerAmount[orderHash];
+    }
+    public async getCancelledTakerAmountAsync(orderHash: string): Promise<BigNumber> {
+        if (_.isUndefined(this.cancelledTakerAmount[orderHash])) {
+            const methodOpts = {
+                defaultBlock: BlockParamLiteral.Pending,
+            };
+            const cancelledTakerAmount = await this.exchange.getCanceledTakerAmountAsync(orderHash, methodOpts);
+            this.setCancelledTakerAmount(orderHash, cancelledTakerAmount);
+        }
+        const cachedCancelled = this.cancelledTakerAmount[orderHash];
+        return cachedCancelled;
+    }
+    public setCancelledTakerAmount(orderHash: string, cancelledTakerAmount: BigNumber): void {
+        this.cancelledTakerAmount[orderHash] = cancelledTakerAmount;
+    }
+    public deleteCancelledTakerAmount(orderHash: string): void {
+        delete this.cancelledTakerAmount[orderHash];
+    }
+    public deleteAll(): void {
+        this.filledTakerAmount = {};
+        this.cancelledTakerAmount = {};
+    }
+}
diff --git a/packages/0x.js/src/subproviders/empty_wallet_subprovider.ts b/packages/0x.js/src/subproviders/empty_wallet_subprovider.ts
new file mode 100644
index 000000000..2f260217c
--- /dev/null
+++ b/packages/0x.js/src/subproviders/empty_wallet_subprovider.ts
@@ -0,0 +1,24 @@
+import {JSONRPCPayload} from '../types';
+
+/*
+ * This class implements the web3-provider-engine subprovider interface and returns
+ * that the provider has no addresses when queried.
+ * Source: https://github.com/MetaMask/provider-engine/blob/master/subproviders/subprovider.js
+ */
+export class EmptyWalletSubProvider {
+    public handleRequest(payload: JSONRPCPayload, next: () => void, end: (err: Error|null, result: any) => void) {
+        switch (payload.method) {
+            case 'eth_accounts':
+                end(null, []);
+                return;
+
+            default:
+                next();
+                return;
+        }
+    }
+    // Required to implement this method despite not needing it for this subprovider
+    public setEngine(engine: any) {
+        // noop
+    }
+}
diff --git a/packages/0x.js/src/types.ts b/packages/0x.js/src/types.ts
new file mode 100644
index 000000000..11683378f
--- /dev/null
+++ b/packages/0x.js/src/types.ts
@@ -0,0 +1,525 @@
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+
+export enum ZeroExError {
+    ContractDoesNotExist = 'CONTRACT_DOES_NOT_EXIST',
+    ExchangeContractDoesNotExist = 'EXCHANGE_CONTRACT_DOES_NOT_EXIST',
+    UnhandledError = 'UNHANDLED_ERROR',
+    UserHasNoAssociatedAddress = 'USER_HAS_NO_ASSOCIATED_ADDRESSES',
+    InvalidSignature = 'INVALID_SIGNATURE',
+    ContractNotDeployedOnNetwork = 'CONTRACT_NOT_DEPLOYED_ON_NETWORK',
+    InsufficientAllowanceForTransfer = 'INSUFFICIENT_ALLOWANCE_FOR_TRANSFER',
+    InsufficientBalanceForTransfer = 'INSUFFICIENT_BALANCE_FOR_TRANSFER',
+    InsufficientEthBalanceForDeposit = 'INSUFFICIENT_ETH_BALANCE_FOR_DEPOSIT',
+    InsufficientWEthBalanceForWithdrawal = 'INSUFFICIENT_WETH_BALANCE_FOR_WITHDRAWAL',
+    InvalidJump = 'INVALID_JUMP',
+    OutOfGas = 'OUT_OF_GAS',
+    NoNetworkId = 'NO_NETWORK_ID',
+    SubscriptionNotFound = 'SUBSCRIPTION_NOT_FOUND',
+    SubscriptionAlreadyPresent = 'SUBSCRIPTION_ALREADY_PRESENT',
+    TransactionMiningTimeout = 'TRANSACTION_MINING_TIMEOUT',
+}
+
+export enum InternalZeroExError {
+    NoAbiDecoder = 'NO_ABI_DECODER',
+    ZrxNotInTokenRegistry = 'ZRX_NOT_IN_TOKEN_REGISTRY',
+}
+
+/**
+ * Elliptic Curve signature
+ */
+export interface ECSignature {
+    v: number;
+    r: string;
+    s: string;
+}
+
+export type OrderAddresses = [string, string, string, string, string];
+
+export type OrderValues = [BigNumber, BigNumber, BigNumber,
+                           BigNumber, BigNumber, BigNumber];
+
+export type LogEvent = Web3.LogEntryEvent;
+export type DecodedLogEvent<ArgsType> = Web3.DecodedLogEntryEvent<ArgsType>;
+
+export type EventCallbackAsync<ArgsType> = (err: null|Error, log?: DecodedLogEvent<ArgsType>) => Promise<void>;
+export type EventCallbackSync<ArgsType> = (err: null|Error, log?: DecodedLogEvent<ArgsType>) => void;
+export type EventCallback<ArgsType> = EventCallbackSync<ArgsType>|EventCallbackAsync<ArgsType>;
+
+export type EventWatcherCallbackSync = (log: LogEvent) => void;
+export type EventWatcherCallbackAsync = (log: LogEvent) => Promise<void>;
+export type EventWatcherCallback = EventWatcherCallbackSync|EventWatcherCallbackAsync;
+
+export interface ExchangeContract extends Web3.ContractInstance {
+    isValidSignature: {
+        callAsync: (signerAddressHex: string, dataHex: string, v: number, r: string, s: string,
+                    txOpts?: TxOpts) => Promise<boolean>;
+    };
+    ZRX_TOKEN_CONTRACT: {
+        callAsync: () => Promise<string>;
+    };
+    TOKEN_TRANSFER_PROXY_CONTRACT: {
+        callAsync: () => Promise<string>;
+    };
+    getUnavailableTakerTokenAmount: {
+        callAsync: (orderHash: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
+    };
+    isRoundingError: {
+        callAsync: (takerTokenFillAmount: BigNumber, takerTokenAmount: BigNumber,
+                    makerTokenAmount: BigNumber, txOpts?: TxOpts) => Promise<boolean>;
+    };
+    fillOrder: {
+        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                               fillTakerTokenAmount: BigNumber,
+                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                               v: number, r: string, s: string, txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                           fillTakerTokenAmount: BigNumber,
+                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                           v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
+    };
+    batchFillOrders: {
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               fillTakerTokenAmounts: BigNumber[],
+                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                               v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           fillTakerTokenAmounts: BigNumber[],
+                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
+    };
+    fillOrdersUpTo: {
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               fillTakerTokenAmount: BigNumber,
+                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                               v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           fillTakerTokenAmount: BigNumber,
+                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
+                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
+    };
+    cancelOrder: {
+        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                               cancelTakerTokenAmount: BigNumber, txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                           cancelTakerTokenAmount: BigNumber,
+                           txOpts?: TxOpts) => Promise<number>;
+    };
+    batchCancelOrders: {
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               cancelTakerTokenAmounts: BigNumber[], txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           cancelTakerTokenAmounts: BigNumber[],
+                           txOpts?: TxOpts) => Promise<number>;
+    };
+    fillOrKillOrder: {
+        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                               fillTakerTokenAmount: BigNumber,
+                               v: number, r: string, s: string, txOpts?: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
+                           fillTakerTokenAmount: BigNumber,
+                           v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
+    };
+    batchFillOrKillOrders: {
+        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                               fillTakerTokenAmounts: BigNumber[],
+                               v: number[], r: string[], s: string[], txOpts: TxOpts) => Promise<string>;
+        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
+                           fillTakerTokenAmounts: BigNumber[],
+                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
+    };
+    filled: {
+        callAsync: (orderHash: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
+    };
+    cancelled: {
+        callAsync: (orderHash: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
+    };
+    getOrderHash: {
+        callAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues) => Promise<string>;
+    };
+}
+
+export interface TokenContract extends Web3.ContractInstance {
+    balanceOf: {
+        callAsync: (address: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
+    };
+    allowance: {
+        callAsync: (ownerAddress: string, allowedAddress: string,
+                    defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
+    };
+    transfer: {
+        sendTransactionAsync: (toAddress: string, amountInBaseUnits: BigNumber,
+                               txOpts?: TxOpts) => Promise<string>;
+    };
+    transferFrom: {
+        sendTransactionAsync: (fromAddress: string, toAddress: string, amountInBaseUnits: BigNumber,
+                               txOpts?: TxOpts) => Promise<string>;
+    };
+    approve: {
+        sendTransactionAsync: (proxyAddress: string, amountInBaseUnits: BigNumber,
+                               txOpts?: TxOpts) => Promise<string>;
+    };
+}
+
+export interface TokenRegistryContract extends Web3.ContractInstance {
+    getTokenMetaData: {
+        callAsync: (address: string) => Promise<TokenMetadata>;
+    };
+    getTokenAddresses: {
+        callAsync: () => Promise<string[]>;
+    };
+    getTokenAddressBySymbol: {
+        callAsync: (symbol: string) => Promise<string>;
+    };
+    getTokenAddressByName: {
+        callAsync: (name: string) => Promise<string>;
+    };
+    getTokenBySymbol: {
+        callAsync: (symbol: string) => Promise<TokenMetadata>;
+    };
+    getTokenByName: {
+        callAsync: (name: string) => Promise<TokenMetadata>;
+    };
+}
+
+export interface EtherTokenContract extends Web3.ContractInstance {
+    deposit: {
+        sendTransactionAsync: (txOpts: TxOpts) => Promise<string>;
+    };
+    withdraw: {
+        sendTransactionAsync: (amount: BigNumber, txOpts: TxOpts) => Promise<string>;
+    };
+}
+
+export interface TokenTransferProxyContract extends Web3.ContractInstance {
+    getAuthorizedAddresses: {
+        callAsync: () => Promise<string[]>;
+    };
+    authorized: {
+        callAsync: (address: string) => Promise<boolean>;
+    };
+}
+
+export enum SolidityTypes {
+    Address = 'address',
+    Uint256 = 'uint256',
+    Uint8 = 'uint8',
+    Uint = 'uint',
+}
+
+export enum ExchangeContractErrCodes {
+    ERROR_FILL_EXPIRED, // Order has already expired
+    ERROR_FILL_NO_VALUE, // Order has already been fully filled or cancelled
+    ERROR_FILL_TRUNCATION, // Rounding error too large
+    ERROR_FILL_BALANCE_ALLOWANCE, // Insufficient balance or allowance for token transfer
+    ERROR_CANCEL_EXPIRED, // Order has already expired
+    ERROR_CANCEL_NO_VALUE, // Order has already been fully filled or cancelled
+}
+
+export enum ExchangeContractErrs {
+    OrderFillExpired = 'ORDER_FILL_EXPIRED',
+    OrderCancelExpired = 'ORDER_CANCEL_EXPIRED',
+    OrderCancelAmountZero = 'ORDER_CANCEL_AMOUNT_ZERO',
+    OrderAlreadyCancelledOrFilled = 'ORDER_ALREADY_CANCELLED_OR_FILLED',
+    OrderFillAmountZero = 'ORDER_FILL_AMOUNT_ZERO',
+    OrderRemainingFillAmountZero = 'ORDER_REMAINING_FILL_AMOUNT_ZERO',
+    OrderFillRoundingError = 'ORDER_FILL_ROUNDING_ERROR',
+    FillBalanceAllowanceError = 'FILL_BALANCE_ALLOWANCE_ERROR',
+    InsufficientTakerBalance = 'INSUFFICIENT_TAKER_BALANCE',
+    InsufficientTakerAllowance = 'INSUFFICIENT_TAKER_ALLOWANCE',
+    InsufficientMakerBalance = 'INSUFFICIENT_MAKER_BALANCE',
+    InsufficientMakerAllowance = 'INSUFFICIENT_MAKER_ALLOWANCE',
+    InsufficientTakerFeeBalance = 'INSUFFICIENT_TAKER_FEE_BALANCE',
+    InsufficientTakerFeeAllowance = 'INSUFFICIENT_TAKER_FEE_ALLOWANCE',
+    InsufficientMakerFeeBalance = 'INSUFFICIENT_MAKER_FEE_BALANCE',
+    InsufficientMakerFeeAllowance = 'INSUFFICIENT_MAKER_FEE_ALLOWANCE',
+    TransactionSenderIsNotFillOrderTaker = 'TRANSACTION_SENDER_IS_NOT_FILL_ORDER_TAKER',
+    MultipleMakersInSingleCancelBatchDisallowed = 'MULTIPLE_MAKERS_IN_SINGLE_CANCEL_BATCH_DISALLOWED',
+    InsufficientRemainingFillAmount = 'INSUFFICIENT_REMAINING_FILL_AMOUNT',
+    MultipleTakerTokensInFillUpToDisallowed = 'MULTIPLE_TAKER_TOKENS_IN_FILL_UP_TO_DISALLOWED',
+    BatchOrdersMustHaveSameExchangeAddress = 'BATCH_ORDERS_MUST_HAVE_SAME_EXCHANGE_ADDRESS',
+    BatchOrdersMustHaveAtLeastOneItem = 'BATCH_ORDERS_MUST_HAVE_AT_LEAST_ONE_ITEM',
+}
+
+export type RawLog = Web3.LogEntry;
+
+export interface ContractEvent {
+    logIndex: number;
+    transactionIndex: number;
+    transactionHash: string;
+    blockHash: string;
+    blockNumber: number;
+    address: string;
+    type: string;
+    event: string;
+    args: ContractEventArgs;
+}
+
+export interface LogFillContractEventArgs {
+    maker: string;
+    taker: string;
+    feeRecipient: string;
+    makerToken: string;
+    takerToken: string;
+    filledMakerTokenAmount: BigNumber;
+    filledTakerTokenAmount: BigNumber;
+    paidMakerFee: BigNumber;
+    paidTakerFee: BigNumber;
+    tokens: string;
+    orderHash: string;
+}
+export interface LogCancelContractEventArgs {
+    maker: string;
+    feeRecipient: string;
+    makerToken: string;
+    takerToken: string;
+    cancelledMakerTokenAmount: BigNumber;
+    cancelledTakerTokenAmount: BigNumber;
+    tokens: string;
+    orderHash: string;
+}
+export interface LogErrorContractEventArgs {
+    errorId: BigNumber;
+    orderHash: string;
+}
+export type ExchangeContractEventArgs = LogFillContractEventArgs|LogCancelContractEventArgs|LogErrorContractEventArgs;
+export interface TransferContractEventArgs {
+    _from: string;
+    _to: string;
+    _value: BigNumber;
+}
+export interface ApprovalContractEventArgs {
+    _owner: string;
+    _spender: string;
+    _value: BigNumber;
+}
+export type TokenContractEventArgs = TransferContractEventArgs|ApprovalContractEventArgs;
+export type ContractEventArgs = ExchangeContractEventArgs|TokenContractEventArgs;
+export type ContractEventArg = string|BigNumber;
+
+export interface Order {
+    maker: string;
+    taker: string;
+    makerFee: BigNumber;
+    takerFee: BigNumber;
+    makerTokenAmount: BigNumber;
+    takerTokenAmount: BigNumber;
+    makerTokenAddress: string;
+    takerTokenAddress: string;
+    salt: BigNumber;
+    exchangeContractAddress: string;
+    feeRecipient: string;
+    expirationUnixTimestampSec: BigNumber;
+}
+
+export interface SignedOrder extends Order {
+    ecSignature: ECSignature;
+}
+
+//                          [address, name, symbol, decimals, ipfsHash, swarmHash]
+export type TokenMetadata = [string, string, string, BigNumber, string, string];
+
+export interface Token {
+    name: string;
+    address: string;
+    symbol: string;
+    decimals: number;
+}
+
+export interface TxOpts {
+    from: string;
+    gas?: number;
+    value?: BigNumber;
+}
+
+export interface TokenAddressBySymbol {
+    [symbol: string]: string;
+}
+
+export enum ExchangeEvents {
+    LogFill = 'LogFill',
+    LogCancel = 'LogCancel',
+    LogError = 'LogError',
+}
+
+export enum TokenEvents {
+    Transfer = 'Transfer',
+    Approval = 'Approval',
+}
+
+export type ContractEvents = TokenEvents|ExchangeEvents;
+
+export interface IndexedFilterValues {
+    [index: string]: ContractEventArg;
+}
+
+export enum BlockParamLiteral {
+    Latest = 'latest',
+    Earliest = 'earliest',
+    Pending = 'pending',
+}
+
+export type BlockParam = BlockParamLiteral|number;
+
+export interface SubscriptionOpts {
+    fromBlock: BlockParam;
+    toBlock: BlockParam;
+}
+
+export type DoneCallback = (err?: Error) => void;
+
+export interface OrderCancellationRequest {
+    order: Order|SignedOrder;
+    takerTokenCancelAmount: BigNumber;
+}
+
+export interface OrderFillRequest {
+    signedOrder: SignedOrder;
+    takerTokenFillAmount: BigNumber;
+}
+
+export type AsyncMethod = (...args: any[]) => Promise<any>;
+
+/**
+ * We re-export the `Web3.Provider` type specified in the Web3 Typescript typings
+ * since it is the type of the `provider` argument to the `ZeroEx` constructor.
+ * It is however a `Web3` library type, not a native `0x.js` type.
+ */
+export type Web3Provider = Web3.Provider;
+
+export interface ExchangeContractByAddress {
+    [address: string]: ExchangeContract;
+}
+
+export interface JSONRPCPayload {
+    params: any[];
+    method: string;
+}
+
+/*
+ * eventPollingIntervalMs: How often to poll the Ethereum node for new events
+ */
+export interface OrderStateWatcherConfig {
+    eventPollingIntervalMs?: number;
+}
+
+/*
+ * gasPrice: Gas price to use with every transaction
+ * exchangeContractAddress: The address of an exchange contract to use
+ * tokenRegistryContractAddress: The address of a token registry contract to use
+ * etherTokenContractAddress: The address of an ether token contract to use
+ * orderWatcherConfig: All the configs related to the orderWatcher
+ */
+export interface ZeroExConfig {
+    gasPrice?: BigNumber; // Gas price to use with every transaction
+    exchangeContractAddress?: string;
+    tokenRegistryContractAddress?: string;
+    etherTokenContractAddress?: string;
+    orderWatcherConfig?: OrderStateWatcherConfig;
+}
+
+export enum AbiType {
+    Function = 'function',
+    Constructor = 'constructor',
+    Event = 'event',
+    Fallback = 'fallback',
+}
+
+export interface DecodedLogArgs {
+    [argName: string]: ContractEventArg;
+}
+
+export interface LogWithDecodedArgs<ArgsType> extends Web3.DecodedLogEntry<ArgsType> {}
+
+export interface TransactionReceiptWithDecodedLogs extends TransactionReceipt {
+    logs: Array<LogWithDecodedArgs<DecodedLogArgs>|Web3.LogEntry>;
+}
+
+export interface Artifact {
+    abi: any;
+    networks: {[networkId: number]: {
+        address: string;
+    }};
+}
+
+/*
+ * expectedFillTakerTokenAmount: If specified, the validation method will ensure that the
+ * supplied order maker has a sufficient allowance/balance to fill this amount of the order's
+ * takerTokenAmount. If not specified, the validation method ensures that the maker has a sufficient
+ * allowance/balance to fill the entire remaining order amount.
+ */
+export interface ValidateOrderFillableOpts {
+    expectedFillTakerTokenAmount?: BigNumber;
+}
+
+/*
+ * defaultBlock: The block up to which to query the blockchain state. Setting this to a historical block number
+ * let's the user query the blockchain's state at an arbitrary point in time. In order for this to work, the
+ * backing  Ethereum node must keep the entire historical state of the chain (e.g setting `--pruning=archive`
+ * flag when  running Parity).
+ */
+export interface MethodOpts {
+    defaultBlock?: Web3.BlockParam;
+}
+
+/*
+ * shouldValidate: Flag indicating whether the library should make attempts to validate a transaction before
+ * broadcasting it. For example, order has a valid signature, maker has sufficient funds, etc.
+ */
+export interface OrderTransactionOpts {
+    shouldValidate: boolean;
+}
+
+export type FilterObject = Web3.FilterObject;
+
+export enum TradeSide {
+    Maker = 'maker',
+    Taker = 'taker',
+}
+
+export enum TransferType {
+    Trade = 'trade',
+    Fee = 'fee',
+}
+
+export interface OrderRelevantState {
+    makerBalance: BigNumber;
+    makerProxyAllowance: BigNumber;
+    makerFeeBalance: BigNumber;
+    makerFeeProxyAllowance: BigNumber;
+    filledTakerTokenAmount: BigNumber;
+    canceledTakerTokenAmount: BigNumber;
+    remainingFillableMakerTokenAmount: BigNumber;
+}
+
+export interface OrderStateValid {
+    isValid: true;
+    orderHash: string;
+    orderRelevantState: OrderRelevantState;
+}
+
+export interface OrderStateInvalid {
+    isValid: false;
+    orderHash: string;
+    error: ExchangeContractErrs;
+}
+
+export type OrderState = OrderStateValid|OrderStateInvalid;
+
+export type OnOrderStateChangeCallbackSync = (orderState: OrderState) => void;
+export type OnOrderStateChangeCallbackAsync = (orderState: OrderState) => Promise<void>;
+export type OnOrderStateChangeCallback = OnOrderStateChangeCallbackAsync|OnOrderStateChangeCallbackSync;
+
+export interface TransactionReceipt {
+    blockHash: string;
+    blockNumber: number;
+    transactionHash: string;
+    transactionIndex: number;
+    from: string;
+    to: string;
+    status: null|0|1;
+    cumulativeGasUsed: number;
+    gasUsed: number;
+    contractAddress: string|null;
+    logs: Web3.LogEntry[];
+}
diff --git a/packages/0x.js/src/utils/abi_decoder.ts b/packages/0x.js/src/utils/abi_decoder.ts
new file mode 100644
index 000000000..840ad9be0
--- /dev/null
+++ b/packages/0x.js/src/utils/abi_decoder.ts
@@ -0,0 +1,68 @@
+import * as Web3 from 'web3';
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {AbiType, DecodedLogArgs, LogWithDecodedArgs, RawLog, SolidityTypes, ContractEventArgs} from '../types';
+import * as SolidityCoder from 'web3/lib/solidity/coder';
+
+export class AbiDecoder {
+    private savedABIs: Web3.AbiDefinition[] = [];
+    private methodIds: {[signatureHash: string]: Web3.EventAbi} = {};
+    constructor(abiArrays: Web3.AbiDefinition[][]) {
+        _.map(abiArrays, this.addABI.bind(this));
+    }
+    // This method can only decode logs from the 0x & ERC20 smart contracts
+    public tryToDecodeLogOrNoop<ArgsType extends ContractEventArgs>(
+        log: Web3.LogEntry): LogWithDecodedArgs<ArgsType>|RawLog {
+        const methodId = log.topics[0];
+        const event = this.methodIds[methodId];
+        if (_.isUndefined(event)) {
+            return log;
+        }
+        const logData = log.data;
+        const decodedParams: DecodedLogArgs = {};
+        let dataIndex = 0;
+        let topicsIndex = 1;
+
+        const nonIndexedInputs = _.filter(event.inputs, input => !input.indexed);
+        const dataTypes = _.map(nonIndexedInputs, input => input.type);
+        const decodedData = SolidityCoder.decodeParams(dataTypes, logData.slice('0x'.length));
+
+        _.map(event.inputs, (param: Web3.EventParameter) => {
+            // Indexed parameters are stored in topics. Non-indexed ones in decodedData
+            let value = param.indexed ? log.topics[topicsIndex++] : decodedData[dataIndex++];
+            if (param.type === SolidityTypes.Address) {
+                value = this.padZeros(new BigNumber(value).toString(16));
+            } else if (param.type === SolidityTypes.Uint256 ||
+                       param.type === SolidityTypes.Uint8 ||
+                       param.type === SolidityTypes.Uint ) {
+                value = new BigNumber(value);
+            }
+            decodedParams[param.name] = value;
+        });
+
+        return {
+            ...log,
+            event: event.name,
+            args: decodedParams,
+        };
+    }
+    private addABI(abiArray: Web3.AbiDefinition[]): void {
+        _.map(abiArray, (abi: Web3.AbiDefinition) => {
+            if (abi.type === AbiType.Event) {
+                const signature = `${abi.name}(${_.map(abi.inputs, input => input.type).join(',')})`;
+                const signatureHash = new Web3().sha3(signature);
+                this.methodIds[signatureHash] = abi;
+            }
+        });
+        this.savedABIs = this.savedABIs.concat(abiArray);
+    }
+    private padZeros(address: string) {
+        let formatted = address;
+        if (_.startsWith(formatted, '0x')) {
+            formatted = formatted.slice(2);
+        }
+
+        formatted = _.padStart(formatted, 40, '0');
+        return `0x${formatted}`;
+    }
+}
diff --git a/packages/0x.js/src/utils/assert.ts b/packages/0x.js/src/utils/assert.ts
new file mode 100644
index 000000000..e5c9439f3
--- /dev/null
+++ b/packages/0x.js/src/utils/assert.ts
@@ -0,0 +1,101 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {SchemaValidator, Schema} from '0x-json-schemas';
+import {Web3Wrapper} from '../web3_wrapper';
+import {signatureUtils} from '../utils/signature_utils';
+import {ECSignature} from '../types';
+
+const HEX_REGEX = /^0x[0-9A-F]*$/i;
+
+export const assert = {
+    isBigNumber(variableName: string, value: BigNumber): void {
+        const isBigNumber = _.isObject(value) && (value as any).isBigNumber;
+        this.assert(isBigNumber, this.typeAssertionMessage(variableName, 'BigNumber', value));
+    },
+    isValidBaseUnitAmount(variableName: string, value: BigNumber) {
+        assert.isBigNumber(variableName, value);
+        const hasDecimals = value.decimalPlaces() !== 0;
+        this.assert(
+            !hasDecimals, `${variableName} should be in baseUnits (no decimals), found value: ${value.toNumber()}`,
+        );
+    },
+    isValidSignature(orderHash: string, ecSignature: ECSignature, signerAddress: string) {
+        const isValidSignature = signatureUtils.isValidSignature(orderHash, ecSignature, signerAddress);
+        this.assert(isValidSignature, `Expected order with hash '${orderHash}' to have a valid signature`);
+    },
+    isUndefined(value: any, variableName?: string): void {
+        this.assert(_.isUndefined(value), this.typeAssertionMessage(variableName, 'undefined', value));
+    },
+    isString(variableName: string, value: string): void {
+        this.assert(_.isString(value), this.typeAssertionMessage(variableName, 'string', value));
+    },
+    isFunction(variableName: string, value: any): void {
+        this.assert(_.isFunction(value), this.typeAssertionMessage(variableName, 'function', value));
+    },
+    isHexString(variableName: string, value: string): void {
+        this.assert(_.isString(value) && HEX_REGEX.test(value),
+            this.typeAssertionMessage(variableName, 'HexString', value));
+    },
+    isETHAddressHex(variableName: string, value: string): void {
+        const web3 = new Web3();
+        this.assert(web3.isAddress(value), this.typeAssertionMessage(variableName, 'ETHAddressHex', value));
+        this.assert(
+            web3.isAddress(value) && value.toLowerCase() === value,
+            `Checksummed addresses are not supported. Convert ${variableName} to lower case before passing`,
+        );
+    },
+    doesBelongToStringEnum(variableName: string, value: string,
+                           stringEnum: any /* There is no base type for every string enum */): void {
+        const doesBelongToStringEnum = !_.isUndefined(stringEnum[value]);
+        const enumValues = _.keys(stringEnum);
+        const enumValuesAsStrings = _.map(enumValues, enumValue => `'${enumValue}'`);
+        const enumValuesAsString = enumValuesAsStrings.join(', ');
+        assert.assert(
+            doesBelongToStringEnum,
+            `Expected ${variableName} to be one of: ${enumValuesAsString}, encountered: ${value}`,
+        );
+    },
+    async isSenderAddressAsync(variableName: string, senderAddressHex: string,
+                               web3Wrapper: Web3Wrapper): Promise<void> {
+        assert.isETHAddressHex(variableName, senderAddressHex);
+        const isSenderAddressAvailable = await web3Wrapper.isSenderAddressAvailableAsync(senderAddressHex);
+        assert.assert(isSenderAddressAvailable,
+            `Specified ${variableName} ${senderAddressHex} isn't available through the supplied web3 provider`,
+        );
+    },
+    async isUserAddressAvailableAsync(web3Wrapper: Web3Wrapper): Promise<void> {
+        const availableAddresses = await web3Wrapper.getAvailableAddressesAsync();
+        this.assert(!_.isEmpty(availableAddresses), 'No addresses were available on the provided web3 provider');
+    },
+    hasAtMostOneUniqueValue(value: any[], errMsg: string): void {
+        this.assert(_.uniq(value).length <= 1, errMsg);
+    },
+    isNumber(variableName: string, value: number): void {
+        this.assert(_.isFinite(value), this.typeAssertionMessage(variableName, 'number', value));
+    },
+    isBoolean(variableName: string, value: boolean): void {
+        this.assert(_.isBoolean(value), this.typeAssertionMessage(variableName, 'boolean', value));
+    },
+    isWeb3Provider(variableName: string, value: Web3.Provider): void {
+        const isWeb3Provider = _.isFunction((value as any).send) || _.isFunction((value as any).sendAsync);
+        this.assert(isWeb3Provider, this.typeAssertionMessage(variableName, 'Web3.Provider', value));
+    },
+    doesConformToSchema(variableName: string, value: any, schema: Schema): void {
+        const schemaValidator = new SchemaValidator();
+        const validationResult = schemaValidator.validate(value, schema);
+        const hasValidationErrors = validationResult.errors.length > 0;
+        const msg = `Expected ${variableName} to conform to schema ${schema.id}
+Encountered: ${JSON.stringify(value, null, '\t')}
+Validation errors: ${validationResult.errors.join(', ')}`;
+        this.assert(!hasValidationErrors, msg);
+    },
+    assert(condition: boolean, message: string): void {
+        if (!condition) {
+            throw new Error(message);
+        }
+    },
+    typeAssertionMessage(variableName: string, type: string, value: any): string {
+        return `Expected ${variableName} to be of type ${type}, encountered: ${value}`;
+    },
+};
diff --git a/packages/0x.js/src/utils/constants.ts b/packages/0x.js/src/utils/constants.ts
new file mode 100644
index 000000000..3de3f5bc1
--- /dev/null
+++ b/packages/0x.js/src/utils/constants.ts
@@ -0,0 +1,11 @@
+import BigNumber from 'bignumber.js';
+
+export const constants = {
+    NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
+    TESTRPC_NETWORK_ID: 50,
+    MAX_DIGITS_IN_UNSIGNED_256_INT: 78,
+    INVALID_JUMP_PATTERN: 'invalid JUMP at',
+    OUT_OF_GAS_PATTERN: 'out of gas',
+    UNLIMITED_ALLOWANCE_IN_BASE_UNITS: new BigNumber(2).pow(256).minus(1),
+    DEFAULT_BLOCK_POLLING_INTERVAL: 1000,
+};
diff --git a/packages/0x.js/src/utils/decorators.ts b/packages/0x.js/src/utils/decorators.ts
new file mode 100644
index 000000000..ec750b891
--- /dev/null
+++ b/packages/0x.js/src/utils/decorators.ts
@@ -0,0 +1,35 @@
+import * as _ from 'lodash';
+import {constants} from './constants';
+import {AsyncMethod, ZeroExError} from '../types';
+
+export const decorators = {
+    /**
+     * Source: https://stackoverflow.com/a/29837695/3546986
+     */
+    contractCallErrorHandler(target: object,
+                             key: string|symbol,
+                             descriptor: TypedPropertyDescriptor<AsyncMethod>,
+    ): TypedPropertyDescriptor<AsyncMethod> {
+        const originalMethod = (descriptor.value as AsyncMethod);
+
+        // Do not use arrow syntax here. Use a function expression in
+        // order to use the correct value of `this` in this method
+        // tslint:disable-next-line:only-arrow-functions
+        descriptor.value =  async function(...args: any[]) {
+            try {
+                const result = await originalMethod.apply(this, args);
+                return result;
+            } catch (error) {
+                if (_.includes(error.message, constants.INVALID_JUMP_PATTERN)) {
+                    throw new Error(ZeroExError.InvalidJump);
+                }
+                if (_.includes(error.message, constants.OUT_OF_GAS_PATTERN)) {
+                    throw new Error(ZeroExError.OutOfGas);
+                }
+                throw error;
+            }
+        };
+
+        return descriptor;
+    },
+};
diff --git a/packages/0x.js/src/utils/exchange_transfer_simulator.ts b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
new file mode 100644
index 000000000..308ef06db
--- /dev/null
+++ b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
@@ -0,0 +1,88 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {ExchangeContractErrs, TradeSide, TransferType, BlockParamLiteral} from '../types';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+
+enum FailureReason {
+    Balance = 'balance',
+    ProxyAllowance = 'proxyAllowance',
+}
+
+const ERR_MSG_MAPPING = {
+    [FailureReason.Balance]: {
+        [TradeSide.Maker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientMakerBalance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeBalance,
+        },
+        [TradeSide.Taker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientTakerBalance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeBalance,
+        },
+    },
+    [FailureReason.ProxyAllowance]: {
+        [TradeSide.Maker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientMakerAllowance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeAllowance,
+        },
+        [TradeSide.Taker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientTakerAllowance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeAllowance,
+        },
+    },
+};
+
+export class ExchangeTransferSimulator {
+    private store: BalanceAndProxyAllowanceLazyStore;
+    private UNLIMITED_ALLOWANCE_IN_BASE_UNITS: BigNumber;
+    constructor(token: TokenWrapper) {
+        this.store = new BalanceAndProxyAllowanceLazyStore(token);
+        this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS = token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
+    }
+    /**
+     * Simulates transferFrom call performed by a proxy
+     * @param  tokenAddress      Address of the token to be transferred
+     * @param  from              Owner of the transferred tokens
+     * @param  to                Recipient of the transferred tokens
+     * @param  amountInBaseUnits The amount of tokens being transferred
+     * @param  tradeSide         Is Maker/Taker transferring
+     * @param  transferType      Is it a fee payment or a value transfer
+     */
+    public async transferFromAsync(tokenAddress: string, from: string, to: string,
+                                   amountInBaseUnits: BigNumber, tradeSide: TradeSide,
+                                   transferType: TransferType): Promise<void> {
+        const balance = await this.store.getBalanceAsync(tokenAddress, from);
+        const proxyAllowance = await this.store.getProxyAllowanceAsync(tokenAddress, from);
+        if (proxyAllowance.lessThan(amountInBaseUnits)) {
+            this.throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
+        }
+        if (balance.lessThan(amountInBaseUnits)) {
+            this.throwValidationError(FailureReason.Balance, tradeSide, transferType);
+        }
+        await this.decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits);
+        await this.decreaseBalanceAsync(tokenAddress, from, amountInBaseUnits);
+        await this.increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
+    }
+    private async decreaseProxyAllowanceAsync(tokenAddress: string, userAddress: string,
+                                              amountInBaseUnits: BigNumber): Promise<void> {
+        const proxyAllowance = await this.store.getProxyAllowanceAsync(tokenAddress, userAddress);
+        if (!proxyAllowance.eq(this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) {
+            this.store.setProxyAllowance(tokenAddress, userAddress, proxyAllowance.minus(amountInBaseUnits));
+        }
+    }
+    private async increaseBalanceAsync(tokenAddress: string, userAddress: string,
+                                       amountInBaseUnits: BigNumber): Promise<void> {
+        const balance = await this.store.getBalanceAsync(tokenAddress, userAddress);
+        this.store.setBalance(tokenAddress, userAddress, balance.plus(amountInBaseUnits));
+    }
+    private async decreaseBalanceAsync(tokenAddress: string, userAddress: string,
+                                       amountInBaseUnits: BigNumber): Promise<void> {
+        const balance = await this.store.getBalanceAsync(tokenAddress, userAddress);
+        this.store.setBalance(tokenAddress, userAddress, balance.minus(amountInBaseUnits));
+    }
+    private throwValidationError(failureReason: FailureReason, tradeSide: TradeSide,
+                                 transferType: TransferType): Promise<never> {
+        const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
+        throw new Error(errMsg);
+    }
+}
diff --git a/packages/0x.js/src/utils/filter_utils.ts b/packages/0x.js/src/utils/filter_utils.ts
new file mode 100644
index 000000000..e09a95a6e
--- /dev/null
+++ b/packages/0x.js/src/utils/filter_utils.ts
@@ -0,0 +1,82 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import * as uuid from 'uuid/v4';
+import * as ethUtil from 'ethereumjs-util';
+import * as jsSHA3 from 'js-sha3';
+import {ContractEvents, IndexedFilterValues, SubscriptionOpts} from '../types';
+
+const TOPIC_LENGTH = 32;
+
+export const filterUtils = {
+    generateUUID(): string {
+        return uuid();
+    },
+    getFilter(address: string, eventName: ContractEvents,
+              indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi,
+              subscriptionOpts?: SubscriptionOpts): Web3.FilterObject {
+        const eventAbi = _.find(abi, {name: eventName}) as Web3.EventAbi;
+        const eventSignature = filterUtils.getEventSignatureFromAbiByName(eventAbi, eventName);
+        const topicForEventSignature = ethUtil.addHexPrefix(jsSHA3.keccak256(eventSignature));
+        const topicsForIndexedArgs = filterUtils.getTopicsForIndexedArgs(eventAbi, indexFilterValues);
+        const topics = [topicForEventSignature, ...topicsForIndexedArgs];
+        let filter: Web3.FilterObject = {
+            address,
+            topics,
+        };
+        if (!_.isUndefined(subscriptionOpts)) {
+            filter = {
+                ...subscriptionOpts,
+                ...filter,
+            };
+        }
+        return filter;
+    },
+    getEventSignatureFromAbiByName(eventAbi: Web3.EventAbi, eventName: ContractEvents): string {
+        const types = _.map(eventAbi.inputs, 'type');
+        const signature = `${eventAbi.name}(${types.join(',')})`;
+        return signature;
+    },
+    getTopicsForIndexedArgs(abi: Web3.EventAbi, indexFilterValues: IndexedFilterValues): Array<string|null> {
+        const topics: Array<string|null> = [];
+        for (const eventInput of abi.inputs) {
+            if (!eventInput.indexed) {
+                continue;
+            }
+            if (_.isUndefined(indexFilterValues[eventInput.name])) {
+                // Null is a wildcard topic in a JSON-RPC call
+                topics.push(null);
+            } else {
+                const value = indexFilterValues[eventInput.name] as string;
+                const buffer = ethUtil.toBuffer(value);
+                const paddedBuffer = ethUtil.setLengthLeft(buffer, TOPIC_LENGTH);
+                const topic = ethUtil.bufferToHex(paddedBuffer);
+                topics.push(topic);
+            }
+        }
+        return topics;
+    },
+    matchesFilter(log: Web3.LogEntry, filter: Web3.FilterObject): boolean {
+        if (!_.isUndefined(filter.address) && log.address !== filter.address) {
+            return false;
+        }
+        if (!_.isUndefined(filter.topics)) {
+            return filterUtils.matchesTopics(log.topics, filter.topics);
+        }
+        return true;
+    },
+    matchesTopics(logTopics: string[], filterTopics: Array<string[]|string|null>): boolean {
+        const matchesTopic = _.zipWith(logTopics, filterTopics, filterUtils.matchesTopic.bind(filterUtils));
+        const matchesTopics = _.every(matchesTopic);
+        return matchesTopics;
+    },
+    matchesTopic(logTopic: string, filterTopic: string[]|string|null): boolean {
+        if (_.isArray(filterTopic)) {
+            return _.includes(filterTopic, logTopic);
+        }
+        if (_.isString(filterTopic)) {
+            return filterTopic === logTopic;
+        }
+        // null topic is a wildcard
+        return true;
+    },
+};
diff --git a/packages/0x.js/src/utils/interval_utils.ts b/packages/0x.js/src/utils/interval_utils.ts
new file mode 100644
index 000000000..62b79f2f5
--- /dev/null
+++ b/packages/0x.js/src/utils/interval_utils.ts
@@ -0,0 +1,20 @@
+import * as _ from 'lodash';
+
+export const intervalUtils = {
+    setAsyncExcludingInterval(fn: () => Promise<void>, intervalMs: number) {
+        let locked = false;
+        const intervalId = setInterval(async () => {
+            if (locked) {
+                return;
+            } else {
+                locked = true;
+                await fn();
+                locked = false;
+            }
+        }, intervalMs);
+        return intervalId;
+    },
+    clearAsyncExcludingInterval(intervalId: NodeJS.Timer): void {
+        clearInterval(intervalId);
+    },
+};
diff --git a/packages/0x.js/src/utils/order_state_utils.ts b/packages/0x.js/src/utils/order_state_utils.ts
new file mode 100644
index 000000000..f82601cae
--- /dev/null
+++ b/packages/0x.js/src/utils/order_state_utils.ts
@@ -0,0 +1,119 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {
+    ExchangeContractErrs,
+    SignedOrder,
+    OrderRelevantState,
+    MethodOpts,
+    OrderState,
+    OrderStateValid,
+    OrderStateInvalid,
+} from '../types';
+import {ZeroEx} from '../0x';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
+import {utils} from '../utils/utils';
+import {constants} from '../utils/constants';
+import {OrderFilledCancelledLazyStore} from '../stores/order_filled_cancelled_lazy_store';
+import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+
+export class OrderStateUtils {
+    private balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore;
+    private orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore;
+    constructor(balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore,
+                orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore) {
+        this.balanceAndProxyAllowanceLazyStore = balanceAndProxyAllowanceLazyStore;
+        this.orderFilledCancelledLazyStore = orderFilledCancelledLazyStore;
+    }
+    public async getOrderStateAsync(signedOrder: SignedOrder): Promise<OrderState> {
+        const orderRelevantState = await this.getOrderRelevantStateAsync(signedOrder);
+        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        try {
+            this.validateIfOrderIsValid(signedOrder, orderRelevantState);
+            const orderState: OrderStateValid = {
+                isValid: true,
+                orderHash,
+                orderRelevantState,
+            };
+            return orderState;
+        } catch (err) {
+            const orderState: OrderStateInvalid = {
+                isValid: false,
+                orderHash,
+                error: err.message,
+            };
+            return orderState;
+        }
+    }
+    public async getOrderRelevantStateAsync(signedOrder: SignedOrder): Promise<OrderRelevantState> {
+        // HACK: We access the private property here but otherwise the interface will be less nice.
+        // If we pass it from the instantiator - there is no opportunity to get it there
+        // because JS doesn't support async constructors.
+        // Moreover - it's cached under the hood so it's equivalent to an async constructor.
+        const exchange = (this.orderFilledCancelledLazyStore as any).exchange as ExchangeWrapper;
+        const zrxTokenAddress = await exchange.getZRXTokenAddressAsync();
+        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        const makerBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker,
+        );
+        const makerProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker,
+        );
+        const makerFeeBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
+            zrxTokenAddress, signedOrder.maker,
+        );
+        const makerFeeProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
+            zrxTokenAddress, signedOrder.maker,
+        );
+        const filledTakerTokenAmount = await this.orderFilledCancelledLazyStore.getFilledTakerAmountAsync(orderHash);
+        const canceledTakerTokenAmount = await this.orderFilledCancelledLazyStore.getCancelledTakerAmountAsync(
+            orderHash,
+        );
+        const unavailableTakerTokenAmount = await exchange.getUnavailableTakerAmountAsync(orderHash);
+        const totalMakerTokenAmount = signedOrder.makerTokenAmount;
+        const totalTakerTokenAmount = signedOrder.takerTokenAmount;
+        const remainingTakerTokenAmount = totalTakerTokenAmount.minus(unavailableTakerTokenAmount);
+        const remainingMakerTokenAmount = remainingTakerTokenAmount.times(totalMakerTokenAmount)
+                                                                   .dividedToIntegerBy(totalTakerTokenAmount);
+        const fillableMakerTokenAmount = BigNumber.min([makerProxyAllowance, makerBalance]);
+        const remainingFillableMakerTokenAmount = BigNumber.min(fillableMakerTokenAmount, remainingMakerTokenAmount);
+        // TODO: Handle edge case where maker token is ZRX with fee
+        const orderRelevantState = {
+            makerBalance,
+            makerProxyAllowance,
+            makerFeeBalance,
+            makerFeeProxyAllowance,
+            filledTakerTokenAmount,
+            canceledTakerTokenAmount,
+            remainingFillableMakerTokenAmount,
+        };
+        return orderRelevantState;
+    }
+    private validateIfOrderIsValid(signedOrder: SignedOrder, orderRelevantState: OrderRelevantState): void {
+        const unavailableTakerTokenAmount = orderRelevantState.canceledTakerTokenAmount.add(
+            orderRelevantState.filledTakerTokenAmount,
+        );
+        const availableTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
+        if (availableTakerTokenAmount.eq(0)) {
+            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
+        }
+
+        if (orderRelevantState.makerBalance.eq(0)) {
+            throw new Error(ExchangeContractErrs.InsufficientMakerBalance);
+        }
+        if (orderRelevantState.makerProxyAllowance.eq(0)) {
+            throw new Error(ExchangeContractErrs.InsufficientMakerAllowance);
+        }
+        if (!signedOrder.makerFee.eq(0)) {
+            if (orderRelevantState.makerFeeBalance.eq(0)) {
+                throw new Error(ExchangeContractErrs.InsufficientMakerFeeBalance);
+            }
+            if (orderRelevantState.makerFeeProxyAllowance.eq(0)) {
+                throw new Error(ExchangeContractErrs.InsufficientMakerFeeAllowance);
+            }
+        }
+        // TODO Add linear function solver when maker token is ZRX #badass
+        // Return the max amount that's fillable
+    }
+}
diff --git a/packages/0x.js/src/utils/order_validation_utils.ts b/packages/0x.js/src/utils/order_validation_utils.ts
new file mode 100644
index 000000000..f03703c4e
--- /dev/null
+++ b/packages/0x.js/src/utils/order_validation_utils.ts
@@ -0,0 +1,166 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {ExchangeContractErrs, SignedOrder, Order, ZeroExError, TradeSide, TransferType} from '../types';
+import {ZeroEx} from '../0x';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
+import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
+import {utils} from '../utils/utils';
+import {constants} from '../utils/constants';
+import {ExchangeTransferSimulator} from './exchange_transfer_simulator';
+
+export class OrderValidationUtils {
+    private tokenWrapper: TokenWrapper;
+    private exchangeWrapper: ExchangeWrapper;
+    constructor(tokenWrapper: TokenWrapper, exchangeWrapper: ExchangeWrapper) {
+        this.tokenWrapper = tokenWrapper;
+        this.exchangeWrapper = exchangeWrapper;
+    }
+    public async validateOrderFillableOrThrowAsync(
+        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder, zrxTokenAddress: string,
+        expectedFillTakerTokenAmount?: BigNumber): Promise<void> {
+        const orderHash = utils.getOrderHashHex(signedOrder);
+        const unavailableTakerTokenAmount = await this.exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
+        this.validateRemainingFillAmountNotZeroOrThrow(
+            signedOrder.takerTokenAmount, unavailableTakerTokenAmount,
+        );
+        this.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
+        let fillTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
+        if (!_.isUndefined(expectedFillTakerTokenAmount)) {
+            fillTakerTokenAmount = expectedFillTakerTokenAmount;
+        }
+        const fillMakerTokenAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerTokenAmount,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker, signedOrder.taker, fillMakerTokenAmount,
+            TradeSide.Maker, TransferType.Trade,
+        );
+        const makerFeeAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, signedOrder.maker, signedOrder.feeRecipient, makerFeeAmount,
+            TradeSide.Maker, TransferType.Fee,
+        );
+    }
+    public async validateFillOrderThrowIfInvalidAsync(
+        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder,
+        fillTakerTokenAmount: BigNumber, takerAddress: string,
+        zrxTokenAddress: string): Promise<BigNumber> {
+        if (fillTakerTokenAmount.eq(0)) {
+            throw new Error(ExchangeContractErrs.OrderFillAmountZero);
+        }
+        const orderHash = utils.getOrderHashHex(signedOrder);
+        if (!ZeroEx.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker)) {
+            throw new Error(ZeroExError.InvalidSignature);
+        }
+        const unavailableTakerTokenAmount = await this.exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
+        this.validateRemainingFillAmountNotZeroOrThrow(
+            signedOrder.takerTokenAmount, unavailableTakerTokenAmount,
+        );
+        if (signedOrder.taker !== constants.NULL_ADDRESS && signedOrder.taker !== takerAddress) {
+            throw new Error(ExchangeContractErrs.TransactionSenderIsNotFillOrderTaker);
+        }
+        this.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
+        const remainingTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
+        const filledTakerTokenAmount = remainingTakerTokenAmount.lessThan(fillTakerTokenAmount) ?
+                                       remainingTakerTokenAmount :
+                                       fillTakerTokenAmount;
+        await this.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+            exchangeTradeEmulator, signedOrder, filledTakerTokenAmount, takerAddress, zrxTokenAddress,
+        );
+
+        const wouldRoundingErrorOccur = await this.exchangeWrapper.isRoundingErrorAsync(
+            filledTakerTokenAmount, signedOrder.takerTokenAmount, signedOrder.makerTokenAmount,
+        );
+        if (wouldRoundingErrorOccur) {
+            throw new Error(ExchangeContractErrs.OrderFillRoundingError);
+        }
+        return filledTakerTokenAmount;
+    }
+    public async validateFillOrKillOrderThrowIfInvalidAsync(
+        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder,
+        fillTakerTokenAmount: BigNumber, takerAddress: string, zrxTokenAddress: string): Promise<void> {
+        const filledTakerTokenAmount = await this.validateFillOrderThrowIfInvalidAsync(
+            exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress,
+        );
+        if (filledTakerTokenAmount !== fillTakerTokenAmount) {
+            throw new Error(ExchangeContractErrs.InsufficientRemainingFillAmount);
+        }
+    }
+    public async validateCancelOrderThrowIfInvalidAsync(order: Order,
+                                                        cancelTakerTokenAmount: BigNumber,
+                                                        unavailableTakerTokenAmount: BigNumber,
+    ): Promise<void> {
+        if (cancelTakerTokenAmount.eq(0)) {
+            throw new Error(ExchangeContractErrs.OrderCancelAmountZero);
+        }
+        if (order.takerTokenAmount.eq(unavailableTakerTokenAmount)) {
+            throw new Error(ExchangeContractErrs.OrderAlreadyCancelledOrFilled);
+        }
+        const currentUnixTimestampSec = utils.getCurrentUnixTimestamp();
+        if (order.expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
+            throw new Error(ExchangeContractErrs.OrderCancelExpired);
+        }
+    }
+    public async validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder,
+        fillTakerTokenAmount: BigNumber, senderAddress: string, zrxTokenAddress: string): Promise<void> {
+        const fillMakerTokenAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerTokenAmount,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker, senderAddress, fillMakerTokenAmount,
+            TradeSide.Maker, TransferType.Trade,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            signedOrder.takerTokenAddress, senderAddress, signedOrder.maker, fillTakerTokenAmount,
+            TradeSide.Taker, TransferType.Trade,
+        );
+        const makerFeeAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, signedOrder.maker, signedOrder.feeRecipient, makerFeeAmount, TradeSide.Maker,
+            TransferType.Fee,
+        );
+        const takerFeeAmount = this.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.takerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, senderAddress, signedOrder.feeRecipient, takerFeeAmount, TradeSide.Taker,
+            TransferType.Fee,
+        );
+    }
+    private validateRemainingFillAmountNotZeroOrThrow(
+        takerTokenAmount: BigNumber, unavailableTakerTokenAmount: BigNumber,
+    ) {
+        if (takerTokenAmount.eq(unavailableTakerTokenAmount)) {
+            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
+        }
+    }
+    private validateOrderNotExpiredOrThrow(expirationUnixTimestampSec: BigNumber) {
+        const currentUnixTimestampSec = utils.getCurrentUnixTimestamp();
+        if (expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
+            throw new Error(ExchangeContractErrs.OrderFillExpired);
+        }
+    }
+    private getPartialAmount(numerator: BigNumber, denominator: BigNumber,
+                             target: BigNumber): BigNumber {
+        const fillMakerTokenAmount = numerator
+                                     .mul(target)
+                                     .div(denominator)
+                                     .round(0);
+        return fillMakerTokenAmount;
+    }
+}
diff --git a/packages/0x.js/src/utils/signature_utils.ts b/packages/0x.js/src/utils/signature_utils.ts
new file mode 100644
index 000000000..d066f8bf0
--- /dev/null
+++ b/packages/0x.js/src/utils/signature_utils.ts
@@ -0,0 +1,44 @@
+import * as ethUtil from 'ethereumjs-util';
+import {ECSignature} from '../types';
+
+export const signatureUtils = {
+    isValidSignature(data: string, signature: ECSignature, signerAddress: string): boolean {
+        const dataBuff = ethUtil.toBuffer(data);
+        const msgHashBuff = ethUtil.hashPersonalMessage(dataBuff);
+        try {
+            const pubKey = ethUtil.ecrecover(
+                msgHashBuff,
+                signature.v,
+                ethUtil.toBuffer(signature.r),
+                ethUtil.toBuffer(signature.s));
+            const retrievedAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
+            return retrievedAddress === signerAddress;
+        } catch (err) {
+            return false;
+        }
+    },
+    parseSignatureHexAsVRS(signatureHex: string): ECSignature {
+        const signatureBuffer = ethUtil.toBuffer(signatureHex);
+        let v = signatureBuffer[0];
+        if (v < 27) {
+            v += 27;
+        }
+        const r = signatureBuffer.slice(1, 33);
+        const s = signatureBuffer.slice(33, 65);
+        const ecSignature: ECSignature = {
+            v,
+            r: ethUtil.bufferToHex(r),
+            s: ethUtil.bufferToHex(s),
+        };
+        return ecSignature;
+    },
+    parseSignatureHexAsRSV(signatureHex: string): ECSignature {
+        const {v, r, s} = ethUtil.fromRpcSig(signatureHex);
+        const ecSignature: ECSignature = {
+            v,
+            r: ethUtil.bufferToHex(r),
+            s: ethUtil.bufferToHex(s),
+        };
+        return ecSignature;
+    },
+};
diff --git a/packages/0x.js/src/utils/utils.ts b/packages/0x.js/src/utils/utils.ts
new file mode 100644
index 000000000..280f3e979
--- /dev/null
+++ b/packages/0x.js/src/utils/utils.ts
@@ -0,0 +1,55 @@
+import * as _ from 'lodash';
+import * as ethABI from 'ethereumjs-abi';
+import * as ethUtil from 'ethereumjs-util';
+import {Order, SignedOrder, SolidityTypes} from '../types';
+import BigNumber from 'bignumber.js';
+import BN = require('bn.js');
+
+export const utils = {
+    /**
+     * Converts BigNumber instance to BN
+     * The only reason we convert to BN is to remain compatible with `ethABI. soliditySHA3` that
+     * expects values of Solidity type `uint` to be passed as type `BN`.
+     * We do not use BN anywhere else in the codebase.
+     */
+    bigNumberToBN(value: BigNumber) {
+        return new BN(value.toString(), 10);
+    },
+    consoleLog(message: string): void {
+        // tslint:disable-next-line: no-console
+        console.log(message);
+    },
+    isParityNode(nodeVersion: string): boolean {
+        return _.includes(nodeVersion, 'Parity');
+    },
+    isTestRpc(nodeVersion: string): boolean {
+        return _.includes(nodeVersion, 'TestRPC');
+    },
+    spawnSwitchErr(name: string, value: any): Error {
+        return new Error(`Unexpected switch value: ${value} encountered for ${name}`);
+    },
+    getOrderHashHex(order: Order|SignedOrder): string {
+        const orderParts = [
+            {value: order.exchangeContractAddress, type: SolidityTypes.Address},
+            {value: order.maker, type: SolidityTypes.Address},
+            {value: order.taker, type: SolidityTypes.Address},
+            {value: order.makerTokenAddress, type: SolidityTypes.Address},
+            {value: order.takerTokenAddress, type: SolidityTypes.Address},
+            {value: order.feeRecipient, type: SolidityTypes.Address},
+            {value: utils.bigNumberToBN(order.makerTokenAmount), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.takerTokenAmount), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.makerFee), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.takerFee), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.expirationUnixTimestampSec), type: SolidityTypes.Uint256},
+            {value: utils.bigNumberToBN(order.salt), type: SolidityTypes.Uint256},
+        ];
+        const types = _.map(orderParts, o => o.type);
+        const values = _.map(orderParts, o => o.value);
+        const hashBuff = ethABI.soliditySHA3(types, values);
+        const hashHex = ethUtil.bufferToHex(hashBuff);
+        return hashHex;
+    },
+    getCurrentUnixTimestamp(): BigNumber {
+        return new BigNumber(Date.now() / 1000);
+    },
+};
diff --git a/packages/0x.js/src/web3_wrapper.ts b/packages/0x.js/src/web3_wrapper.ts
new file mode 100644
index 000000000..c937f9288
--- /dev/null
+++ b/packages/0x.js/src/web3_wrapper.ts
@@ -0,0 +1,172 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import promisify = require('es6-promisify');
+import {ZeroExError, Artifact, TransactionReceipt} from './types';
+import {Contract} from './contract';
+
+export class Web3Wrapper {
+    private web3: Web3;
+    private defaults: Partial<Web3.TxData>;
+    private networkIdIfExists?: number;
+    private jsonRpcRequestId: number;
+    constructor(provider: Web3.Provider, defaults?: Partial<Web3.TxData>) {
+        if (_.isUndefined((provider as any).sendAsync)) {
+            // Web3@1.0 provider doesn't support synchronous http requests,
+            // so it only has an async `send` method, instead of a `send` and `sendAsync` in web3@0.x.x`
+            // We re-assign the send method so that Web3@1.0 providers work with 0x.js
+            (provider as any).sendAsync = (provider as any).send;
+        }
+        this.web3 = new Web3();
+        this.web3.setProvider(provider);
+        this.defaults = defaults || {};
+        this.jsonRpcRequestId = 0;
+    }
+    public setProvider(provider: Web3.Provider) {
+        delete this.networkIdIfExists;
+        this.web3.setProvider(provider);
+    }
+    public isAddress(address: string): boolean {
+        return this.web3.isAddress(address);
+    }
+    public async isSenderAddressAvailableAsync(senderAddress: string): Promise<boolean> {
+        const addresses = await this.getAvailableAddressesAsync();
+        return _.includes(addresses, senderAddress);
+    }
+    public async getNodeVersionAsync(): Promise<string> {
+        const nodeVersion = await promisify(this.web3.version.getNode)();
+        return nodeVersion;
+    }
+    public async getTransactionReceiptAsync(txHash: string): Promise<TransactionReceipt> {
+        const transactionReceipt = await promisify(this.web3.eth.getTransactionReceipt)(txHash);
+        transactionReceipt.status = this.normalizeTxReceiptStatus(transactionReceipt.status);
+        return transactionReceipt;
+    }
+    public getCurrentProvider(): Web3.Provider {
+        return this.web3.currentProvider;
+    }
+    public async getNetworkIdIfExistsAsync(): Promise<number|undefined> {
+        if (!_.isUndefined(this.networkIdIfExists)) {
+          return this.networkIdIfExists;
+        }
+
+        try {
+            const networkId = await this.getNetworkAsync();
+            this.networkIdIfExists = Number(networkId);
+            return this.networkIdIfExists;
+        } catch (err) {
+            return undefined;
+        }
+    }
+    public async getContractInstanceFromArtifactAsync<A extends Web3.ContractInstance>(artifact: Artifact,
+                                                                                       address?: string): Promise<A> {
+        let contractAddress: string;
+        if (_.isUndefined(address)) {
+            const networkIdIfExists = await this.getNetworkIdIfExistsAsync();
+            if (_.isUndefined(networkIdIfExists)) {
+                throw new Error(ZeroExError.NoNetworkId);
+            }
+            if (_.isUndefined(artifact.networks[networkIdIfExists])) {
+                throw new Error(ZeroExError.ContractNotDeployedOnNetwork);
+            }
+            contractAddress = artifact.networks[networkIdIfExists].address.toLowerCase();
+        } else {
+            contractAddress = address;
+        }
+        const doesContractExist = await this.doesContractExistAtAddressAsync(contractAddress);
+        if (!doesContractExist) {
+            throw new Error(ZeroExError.ContractDoesNotExist);
+        }
+        const contractInstance = this.getContractInstance<A>(
+            artifact.abi, contractAddress,
+        );
+        return contractInstance;
+    }
+    public toWei(ethAmount: BigNumber): BigNumber {
+        const balanceWei = this.web3.toWei(ethAmount, 'ether');
+        return balanceWei;
+    }
+    public async getBalanceInWeiAsync(owner: string): Promise<BigNumber> {
+        let balanceInWei = await promisify(this.web3.eth.getBalance)(owner);
+        balanceInWei = new BigNumber(balanceInWei);
+        return balanceInWei;
+    }
+    public async doesContractExistAtAddressAsync(address: string): Promise<boolean> {
+        const code = await promisify(this.web3.eth.getCode)(address);
+        // Regex matches 0x0, 0x00, 0x in order to accommodate poorly implemented clients
+        const codeIsEmpty = /^0x0{0,40}$/i.test(code);
+        return !codeIsEmpty;
+    }
+    public async signTransactionAsync(address: string, message: string): Promise<string> {
+        const signData = await promisify(this.web3.eth.sign)(address, message);
+        return signData;
+    }
+    public async getBlockNumberAsync(): Promise<number> {
+        const blockNumber = await promisify(this.web3.eth.getBlockNumber)();
+        return blockNumber;
+    }
+    public async getBlockAsync(blockParam: string|Web3.BlockParam): Promise<Web3.BlockWithoutTransactionData> {
+        const block = await promisify(this.web3.eth.getBlock)(blockParam);
+        return block;
+    }
+    public async getBlockTimestampAsync(blockParam: string|Web3.BlockParam): Promise<number> {
+        const {timestamp} = await this.getBlockAsync(blockParam);
+        return timestamp;
+    }
+    public async getAvailableAddressesAsync(): Promise<string[]> {
+        const addresses: string[] = await promisify(this.web3.eth.getAccounts)();
+        return addresses;
+    }
+    public async getLogsAsync(filter: Web3.FilterObject): Promise<Web3.LogEntry[]> {
+        let fromBlock = filter.fromBlock;
+        if (_.isNumber(fromBlock)) {
+            fromBlock = this.web3.toHex(fromBlock);
+        }
+        let toBlock = filter.toBlock;
+        if (_.isNumber(toBlock)) {
+            toBlock = this.web3.toHex(toBlock);
+        }
+        const serializedFilter = {
+            ...filter,
+            fromBlock,
+            toBlock,
+        };
+        const payload = {
+            jsonrpc: '2.0',
+            id: this.jsonRpcRequestId++,
+            method: 'eth_getLogs',
+            params: [serializedFilter],
+        };
+        const logs = await this.sendRawPayloadAsync(payload);
+        return logs;
+    }
+    private getContractInstance<A extends Web3.ContractInstance>(abi: Web3.ContractAbi, address: string): A {
+        const web3ContractInstance = this.web3.eth.contract(abi).at(address);
+        const contractInstance = new Contract(web3ContractInstance, this.defaults) as any as A;
+        return contractInstance;
+    }
+    private async getNetworkAsync(): Promise<number> {
+        const networkId = await promisify(this.web3.version.getNetwork)();
+        return networkId;
+    }
+    private async sendRawPayloadAsync(payload: Web3.JSONRPCRequestPayload): Promise<any> {
+        const sendAsync = this.web3.currentProvider.sendAsync.bind(this.web3.currentProvider);
+        const response = await promisify(sendAsync)(payload);
+        const result = response.result;
+        return result;
+    }
+    private normalizeTxReceiptStatus(status: undefined|null|string|0|1): null|0|1 {
+        // Transaction status might have four values
+        // undefined - Testrpc and other old clients
+        // null - New clients on old transactions
+        // number - Parity
+        // hex - Geth
+        if (_.isString(status)) {
+            return this.web3.toDecimal(status) as 0|1;
+        } else if (_.isUndefined(status)) {
+            return null;
+        } else {
+            return status;
+        }
+    }
+}
diff --git a/packages/0x.js/test/0x.js_test.ts b/packages/0x.js/test/0x.js_test.ts
new file mode 100644
index 000000000..d56acc38b
--- /dev/null
+++ b/packages/0x.js/test/0x.js_test.ts
@@ -0,0 +1,259 @@
+import * as _ from 'lodash';
+import * as chai from 'chai';
+import {chaiSetup} from './utils/chai_setup';
+import 'mocha';
+import BigNumber from 'bignumber.js';
+import * as Sinon from 'sinon';
+import {ZeroEx, Order, ZeroExError, LogWithDecodedArgs, ApprovalContractEventArgs, TokenEvents} from '../src';
+import {constants} from './utils/constants';
+import {TokenUtils} from './utils/token_utils';
+import {web3Factory} from './utils/web3_factory';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+
+const blockchainLifecycle = new BlockchainLifecycle();
+chaiSetup.configure();
+const expect = chai.expect;
+
+describe('ZeroEx library', () => {
+    const web3 = web3Factory.create();
+    const zeroEx = new ZeroEx(web3.currentProvider);
+    describe('#setProvider', () => {
+        it('overrides provider in nested web3s and invalidates contractInstances', async () => {
+            // Instantiate the contract instances with the current provider
+            await (zeroEx.exchange as any)._getExchangeContractAsync();
+            await (zeroEx.tokenRegistry as any)._getTokenRegistryContractAsync();
+            expect((zeroEx.exchange as any)._exchangeContractIfExists).to.not.be.undefined();
+            expect((zeroEx.tokenRegistry as any)._tokenRegistryContractIfExists).to.not.be.undefined();
+
+            const newProvider = web3Factory.getRpcProvider();
+            // Add property to newProvider so that we can differentiate it from old provider
+            (newProvider as any).zeroExTestId = 1;
+            await zeroEx.setProviderAsync(newProvider);
+
+            // Check that contractInstances with old provider are removed after provider update
+            expect((zeroEx.exchange as any)._exchangeContractIfExists).to.be.undefined();
+            expect((zeroEx.tokenRegistry as any)._tokenRegistryContractIfExists).to.be.undefined();
+
+            // Check that all nested web3 wrapper instances return the updated provider
+            const nestedWeb3WrapperProvider = (zeroEx as any)._web3Wrapper.getCurrentProvider();
+            expect((nestedWeb3WrapperProvider as any).zeroExTestId).to.be.a('number');
+            const exchangeWeb3WrapperProvider = (zeroEx.exchange as any)._web3Wrapper.getCurrentProvider();
+            expect((exchangeWeb3WrapperProvider as any).zeroExTestId).to.be.a('number');
+            const tokenRegistryWeb3WrapperProvider = (zeroEx.tokenRegistry as any)._web3Wrapper.getCurrentProvider();
+            expect((tokenRegistryWeb3WrapperProvider as any).zeroExTestId).to.be.a('number');
+        });
+    });
+    describe('#isValidSignature', () => {
+        // The Exchange smart contract `isValidSignature` method only validates orderHashes and assumes
+        // the length of the data is exactly 32 bytes. Thus for these tests, we use data of this size.
+        const dataHex = '0x6927e990021d23b1eb7b8789f6a6feaf98fe104bb0cf8259421b79f9a34222b0';
+        const signature = {
+            v: 27,
+            r: '0x61a3ed31b43c8780e905a260a35faefcc527be7516aa11c0256729b5b351bc33',
+            s: '0x40349190569279751135161d22529dc25add4f6069af05be04cacbda2ace2254',
+        };
+        const address = '0x5409ed021d9299bf6814279a6a1411a7e866a631';
+        it('should return false if the data doesn\'t pertain to the signature & address', async () => {
+            expect(ZeroEx.isValidSignature('0x0', signature, address)).to.be.false();
+            return expect(
+                (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync('0x0', signature, address),
+            ).to.become(false);
+        });
+        it('should return false if the address doesn\'t pertain to the signature & data', async () => {
+            const validUnrelatedAddress = '0x8b0292b11a196601ed2ce54b665cafeca0347d42';
+            expect(ZeroEx.isValidSignature(dataHex, signature, validUnrelatedAddress)).to.be.false();
+            return expect(
+                (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync(dataHex, signature,
+                                                                                validUnrelatedAddress),
+            ).to.become(false);
+        });
+        it('should return false if the signature doesn\'t pertain to the dataHex & address', async () => {
+            const wrongSignature = _.assign({}, signature, {v: 28});
+            expect(ZeroEx.isValidSignature(dataHex, wrongSignature, address)).to.be.false();
+            return expect(
+                (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync(dataHex, wrongSignature, address),
+            ).to.become(false);
+        });
+        it('should return true if the signature does pertain to the dataHex & address', async () => {
+            const isValidSignatureLocal = ZeroEx.isValidSignature(dataHex, signature, address);
+            expect(isValidSignatureLocal).to.be.true();
+            const isValidSignatureOnContract = await (zeroEx.exchange as any)
+                ._isValidSignatureUsingContractCallAsync(dataHex, signature, address);
+            return expect(isValidSignatureOnContract).to.be.true();
+        });
+    });
+    describe('#generateSalt', () => {
+        it('generates different salts', () => {
+            const equal = ZeroEx.generatePseudoRandomSalt().eq(ZeroEx.generatePseudoRandomSalt());
+            expect(equal).to.be.false();
+        });
+        it('generates salt in range [0..2^256)', () => {
+            const salt = ZeroEx.generatePseudoRandomSalt();
+            expect(salt.greaterThanOrEqualTo(0)).to.be.true();
+            const twoPow256 = new BigNumber(2).pow(256);
+            expect(salt.lessThan(twoPow256)).to.be.true();
+        });
+    });
+    describe('#isValidOrderHash', () => {
+        it('returns false if the value is not a hex string', () => {
+            const isValid = ZeroEx.isValidOrderHash('not a hex');
+            expect(isValid).to.be.false();
+        });
+        it('returns false if the length is wrong', () => {
+            const isValid = ZeroEx.isValidOrderHash('0xdeadbeef');
+            expect(isValid).to.be.false();
+        });
+        it('returns true if order hash is correct', () => {
+            const isValid = ZeroEx.isValidOrderHash('0x' + Array(65).join('0'));
+            expect(isValid).to.be.true();
+        });
+    });
+    describe('#toUnitAmount', () => {
+        it('Should return the expected unit amount for the decimals passed in', () => {
+            const baseUnitAmount = new BigNumber(1000000000);
+            const decimals = 6;
+            const unitAmount = ZeroEx.toUnitAmount(baseUnitAmount, decimals);
+            const expectedUnitAmount = new BigNumber(1000);
+            expect(unitAmount).to.be.bignumber.equal(expectedUnitAmount);
+        });
+    });
+    describe('#toBaseUnitAmount', () => {
+        it('Should return the expected base unit amount for the decimals passed in', () => {
+            const unitAmount = new BigNumber(1000);
+            const decimals = 6;
+            const baseUnitAmount = ZeroEx.toBaseUnitAmount(unitAmount, decimals);
+            const expectedUnitAmount = new BigNumber(1000000000);
+            expect(baseUnitAmount).to.be.bignumber.equal(expectedUnitAmount);
+        });
+    });
+    describe('#getOrderHashHex', () => {
+        const expectedOrderHash = '0x39da987067a3c9e5f1617694f1301326ba8c8b0498ebef5df4863bed394e3c83';
+        const fakeExchangeContractAddress = '0xb69e673309512a9d726f87304c6984054f87a93b';
+        const order: Order = {
+            maker: constants.NULL_ADDRESS,
+            taker: constants.NULL_ADDRESS,
+            feeRecipient: constants.NULL_ADDRESS,
+            makerTokenAddress: constants.NULL_ADDRESS,
+            takerTokenAddress: constants.NULL_ADDRESS,
+            exchangeContractAddress: fakeExchangeContractAddress,
+            salt: new BigNumber(0),
+            makerFee: new BigNumber(0),
+            takerFee: new BigNumber(0),
+            makerTokenAmount: new BigNumber(0),
+            takerTokenAmount: new BigNumber(0),
+            expirationUnixTimestampSec: new BigNumber(0),
+        };
+        it('calculates the order hash', async () => {
+            const orderHash = ZeroEx.getOrderHashHex(order);
+            expect(orderHash).to.be.equal(expectedOrderHash);
+        });
+    });
+    describe('#signOrderHashAsync', () => {
+        let stubs: Sinon.SinonStub[] = [];
+        let makerAddress: string;
+        before(async () => {
+            const availableAddreses = await zeroEx.getAvailableAddressesAsync();
+            makerAddress = availableAddreses[0];
+        });
+        afterEach(() => {
+            // clean up any stubs after the test has completed
+            _.each(stubs, s => s.restore());
+            stubs = [];
+        });
+        it('Should return the correct ECSignature', async () => {
+            const orderHash = '0x6927e990021d23b1eb7b8789f6a6feaf98fe104bb0cf8259421b79f9a34222b0';
+            const expectedECSignature = {
+                v: 27,
+                r: '0x61a3ed31b43c8780e905a260a35faefcc527be7516aa11c0256729b5b351bc33',
+                s: '0x40349190569279751135161d22529dc25add4f6069af05be04cacbda2ace2254',
+            };
+            const ecSignature = await zeroEx.signOrderHashAsync(orderHash, makerAddress);
+            expect(ecSignature).to.deep.equal(expectedECSignature);
+        });
+        it('should return the correct ECSignature for signatureHex concatenated as R + S + V', async () => {
+            const orderHash = '0x34decbedc118904df65f379a175bb39ca18209d6ce41d5ed549d54e6e0a95004';
+            // tslint:disable-next-line: max-line-length
+            const signature = '0x22109d11d79cb8bf96ed88625e1cd9558800c4073332a9a02857499883ee5ce3050aa3cc1f2c435e67e114cdce54b9527b4f50548342401bc5d2b77adbdacb021b';
+            const expectedECSignature = {
+                v: 27,
+                r: '0x22109d11d79cb8bf96ed88625e1cd9558800c4073332a9a02857499883ee5ce3',
+                s: '0x050aa3cc1f2c435e67e114cdce54b9527b4f50548342401bc5d2b77adbdacb02',
+            };
+            stubs = [
+                Sinon.stub((zeroEx as any)._web3Wrapper, 'signTransactionAsync')
+                    .returns(Promise.resolve(signature)),
+                Sinon.stub(ZeroEx, 'isValidSignature').returns(true),
+            ];
+
+            const ecSignature = await zeroEx.signOrderHashAsync(orderHash, makerAddress);
+            expect(ecSignature).to.deep.equal(expectedECSignature);
+        });
+        it('should return the correct ECSignature for signatureHex concatenated as V + R + S', async () => {
+            const orderHash = '0xc793e33ffded933b76f2f48d9aa3339fc090399d5e7f5dec8d3660f5480793f7';
+            // tslint:disable-next-line: max-line-length
+            const signature = '0x1bc80bedc6756722672753413efdd749b5adbd4fd552595f59c13427407ee9aee02dea66f25a608bbae457e020fb6decb763deb8b7192abab624997242da248960';
+            const expectedECSignature = {
+                v: 27,
+                r: '0xc80bedc6756722672753413efdd749b5adbd4fd552595f59c13427407ee9aee0',
+                s: '0x2dea66f25a608bbae457e020fb6decb763deb8b7192abab624997242da248960',
+            };
+            stubs = [
+                Sinon.stub((zeroEx as any)._web3Wrapper, 'signTransactionAsync')
+                    .returns(Promise.resolve(signature)),
+                Sinon.stub(ZeroEx, 'isValidSignature').returns(true),
+            ];
+
+            const ecSignature = await zeroEx.signOrderHashAsync(orderHash, makerAddress);
+            expect(ecSignature).to.deep.equal(expectedECSignature);
+        });
+    });
+    describe('#awaitTransactionMinedAsync', () => {
+        beforeEach(async () => {
+            await blockchainLifecycle.startAsync();
+        });
+        afterEach(async () => {
+            await blockchainLifecycle.revertAsync();
+        });
+        it('returns transaction receipt with decoded logs', async () => {
+            const availableAddresses = await zeroEx.getAvailableAddressesAsync();
+            const coinbase = availableAddresses[0];
+            const tokens = await zeroEx.tokenRegistry.getTokensAsync();
+            const tokenUtils = new TokenUtils(tokens);
+            const zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
+            const proxyAddress = await zeroEx.proxy.getContractAddressAsync();
+            const txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(zrxTokenAddress, coinbase);
+            const txReceiptWithDecodedLogs = await zeroEx.awaitTransactionMinedAsync(txHash);
+            const log = txReceiptWithDecodedLogs.logs[0] as LogWithDecodedArgs<ApprovalContractEventArgs>;
+            expect(log.event).to.be.equal(TokenEvents.Approval);
+            expect(log.args._owner).to.be.equal(coinbase);
+            expect(log.args._spender).to.be.equal(proxyAddress);
+            expect(log.args._value).to.be.bignumber.equal(zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+        });
+    });
+    describe('#config', () => {
+        it('allows to specify exchange contract address', async () => {
+            const config = {
+                exchangeContractAddress: ZeroEx.NULL_ADDRESS,
+            };
+            const zeroExWithWrongExchangeAddress = new ZeroEx(web3.currentProvider, config);
+            return expect(zeroExWithWrongExchangeAddress.exchange.getContractAddressAsync())
+                .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+        });
+        it('allows to specify ether token contract address', async () => {
+            const config = {
+                etherTokenContractAddress: ZeroEx.NULL_ADDRESS,
+            };
+            const zeroExWithWrongEtherTokenAddress = new ZeroEx(web3.currentProvider, config);
+            return expect(zeroExWithWrongEtherTokenAddress.etherToken.getContractAddressAsync())
+                .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+        });
+        it('allows to specify token registry token contract address', async () => {
+            const config = {
+                tokenRegistryContractAddress: ZeroEx.NULL_ADDRESS,
+            };
+            const zeroExWithWrongTokenRegistryAddress = new ZeroEx(web3.currentProvider, config);
+            return expect(zeroExWithWrongTokenRegistryAddress.tokenRegistry.getContractAddressAsync())
+                .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+        });
+    });
+});
diff --git a/packages/0x.js/test/artifacts_test.ts b/packages/0x.js/test/artifacts_test.ts
new file mode 100644
index 000000000..b2866a1d6
--- /dev/null
+++ b/packages/0x.js/test/artifacts_test.ts
@@ -0,0 +1,49 @@
+import * as fs from 'fs';
+import * as chai from 'chai';
+import {chaiSetup} from './utils/chai_setup';
+import HDWalletProvider = require('truffle-hdwallet-provider');
+import {ZeroEx} from '../src';
+import {constants} from './utils/constants';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+// Those tests are slower cause they're talking to a remote node
+const TIMEOUT = 10000;
+
+describe('Artifacts', () => {
+    describe('contracts are deployed on kovan', () => {
+        const kovanRpcUrl = constants.KOVAN_RPC_URL;
+        const packageJSONContent = fs.readFileSync('package.json', 'utf-8');
+        const packageJSON = JSON.parse(packageJSONContent);
+        const mnemonic = packageJSON.config.mnemonic;
+        const web3Provider = new HDWalletProvider(mnemonic, kovanRpcUrl);
+        const zeroEx = new ZeroEx(web3Provider);
+        it('token registry contract is deployed', async () => {
+            await (zeroEx.tokenRegistry as any)._getTokenRegistryContractAsync();
+        }).timeout(TIMEOUT);
+        it('proxy contract is deployed', async () => {
+            await (zeroEx.token as any)._getTokenTransferProxyAddressAsync();
+        }).timeout(TIMEOUT);
+        it('exchange contract is deployed', async () => {
+            await zeroEx.exchange.getContractAddressAsync();
+        }).timeout(TIMEOUT);
+    });
+    describe('contracts are deployed on ropsten', () => {
+        const ropstenRpcUrl = constants.ROPSTEN_RPC_URL;
+        const packageJSONContent = fs.readFileSync('package.json', 'utf-8');
+        const packageJSON = JSON.parse(packageJSONContent);
+        const mnemonic = packageJSON.config.mnemonic;
+        const web3Provider = new HDWalletProvider(mnemonic, ropstenRpcUrl);
+        const zeroEx = new ZeroEx(web3Provider);
+        it('token registry contract is deployed', async () => {
+            await (zeroEx.tokenRegistry as any)._getTokenRegistryContractAsync();
+        }).timeout(TIMEOUT);
+        it('proxy contract is deployed', async () => {
+            await (zeroEx.token as any)._getTokenTransferProxyAddressAsync();
+        }).timeout(TIMEOUT);
+        it('exchange contract is deployed', async () => {
+            await zeroEx.exchange.getContractAddressAsync();
+        }).timeout(TIMEOUT);
+    });
+});
diff --git a/packages/0x.js/test/assert_test.ts b/packages/0x.js/test/assert_test.ts
new file mode 100644
index 000000000..bfca95d9c
--- /dev/null
+++ b/packages/0x.js/test/assert_test.ts
@@ -0,0 +1,34 @@
+import * as chai from 'chai';
+import 'mocha';
+import {ZeroEx} from '../src';
+import {assert} from '../src/utils/assert';
+import {web3Factory} from './utils/web3_factory';
+
+const expect = chai.expect;
+
+describe('Assertion library', () => {
+    const web3 = web3Factory.create();
+    const zeroEx = new ZeroEx(web3.currentProvider);
+    describe('#isSenderAddressHexAsync', () => {
+        it('throws when address is invalid', async () => {
+            const address = '0xdeadbeef';
+            const varName = 'address';
+            return expect(assert.isSenderAddressAsync(varName, address, (zeroEx as any)._web3Wrapper))
+                .to.be.rejectedWith(`Expected ${varName} to be of type ETHAddressHex, encountered: ${address}`);
+        });
+        it('throws when address is unavailable', async () => {
+            const validUnrelatedAddress = '0x8b0292b11a196601eddce54b665cafeca0347d42';
+            const varName = 'address';
+            return expect(assert.isSenderAddressAsync(varName, validUnrelatedAddress, (zeroEx as any)._web3Wrapper))
+                .to.be.rejectedWith(
+                    `Specified ${varName} ${validUnrelatedAddress} isn't available through the supplied web3 provider`,
+                );
+        });
+        it('doesn\'t throw if address is available', async () => {
+            const availableAddress = (await zeroEx.getAvailableAddressesAsync())[0];
+            const varName = 'address';
+            return expect(assert.isSenderAddressAsync(varName, availableAddress, (zeroEx as any)._web3Wrapper))
+                .to.become(undefined);
+        });
+    });
+});
diff --git a/packages/0x.js/test/ether_token_wrapper_test.ts b/packages/0x.js/test/ether_token_wrapper_test.ts
new file mode 100644
index 000000000..ba679d1a1
--- /dev/null
+++ b/packages/0x.js/test/ether_token_wrapper_test.ts
@@ -0,0 +1,111 @@
+import 'mocha';
+import * as chai from 'chai';
+import {chaiSetup} from './utils/chai_setup';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {web3Factory} from './utils/web3_factory';
+import {ZeroEx, ZeroExError} from '../src';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+// Since the address depositing/withdrawing ETH/WETH also needs to pay gas costs for the transaction,
+// a small amount of ETH will be used to pay this gas cost. We therefore check that the difference between
+// the expected balance and actual balance (given the amount of ETH deposited), only deviates by the amount
+// required to pay gas costs.
+const MAX_REASONABLE_GAS_COST_IN_WEI = 62237;
+
+describe('EtherTokenWrapper', () => {
+    let web3: Web3;
+    let zeroEx: ZeroEx;
+    let userAddresses: string[];
+    let addressWithETH: string;
+    let wethContractAddress: string;
+    let depositWeiAmount: BigNumber;
+    let decimalPlaces: number;
+    const gasPrice = new BigNumber(1);
+    const zeroExConfig = {
+        gasPrice,
+    };
+    before(async () => {
+        web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider, zeroExConfig);
+        userAddresses = await zeroEx.getAvailableAddressesAsync();
+        addressWithETH = userAddresses[0];
+        wethContractAddress = await zeroEx.etherToken.getContractAddressAsync();
+        depositWeiAmount = (zeroEx as any)._web3Wrapper.toWei(new BigNumber(5));
+        decimalPlaces = 7;
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('#depositAsync', () => {
+        it('should successfully deposit ETH and issue Wrapped ETH tokens', async () => {
+            const preETHBalance = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
+            const preWETHBalance = await zeroEx.token.getBalanceAsync(wethContractAddress, addressWithETH);
+            expect(preETHBalance).to.be.bignumber.gt(0);
+            expect(preWETHBalance).to.be.bignumber.equal(0);
+
+            const txHash = await zeroEx.etherToken.depositAsync(depositWeiAmount, addressWithETH);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+
+            const postETHBalanceInWei = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
+            const postWETHBalanceInBaseUnits = await zeroEx.token.getBalanceAsync(wethContractAddress, addressWithETH);
+
+            expect(postWETHBalanceInBaseUnits).to.be.bignumber.equal(depositWeiAmount);
+            const remainingETHInWei = preETHBalance.minus(depositWeiAmount);
+            const gasCost = remainingETHInWei.minus(postETHBalanceInWei);
+            expect(gasCost).to.be.bignumber.lte(MAX_REASONABLE_GAS_COST_IN_WEI);
+        });
+        it('should throw if user has insufficient ETH balance for deposit', async () => {
+            const preETHBalance = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
+
+            const extraETHBalance = (zeroEx as any)._web3Wrapper.toWei(5, 'ether');
+            const overETHBalanceinWei = preETHBalance.add(extraETHBalance);
+
+            return expect(
+                zeroEx.etherToken.depositAsync(overETHBalanceinWei, addressWithETH),
+            ).to.be.rejectedWith(ZeroExError.InsufficientEthBalanceForDeposit);
+        });
+    });
+    describe('#withdrawAsync', () => {
+        it('should successfully withdraw ETH in return for Wrapped ETH tokens', async () => {
+            const ETHBalanceInWei = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
+
+            await zeroEx.etherToken.depositAsync(depositWeiAmount, addressWithETH);
+
+            const expectedPreETHBalance = ETHBalanceInWei.minus(depositWeiAmount);
+            const preETHBalance = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
+            const preWETHBalance = await zeroEx.token.getBalanceAsync(wethContractAddress, addressWithETH);
+            let gasCost = expectedPreETHBalance.minus(preETHBalance);
+            expect(gasCost).to.be.bignumber.lte(MAX_REASONABLE_GAS_COST_IN_WEI);
+            expect(preWETHBalance).to.be.bignumber.equal(depositWeiAmount);
+
+            const txHash = await zeroEx.etherToken.withdrawAsync(depositWeiAmount, addressWithETH);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+
+            const postETHBalance = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
+            const postWETHBalanceInBaseUnits = await zeroEx.token.getBalanceAsync(wethContractAddress, addressWithETH);
+
+            expect(postWETHBalanceInBaseUnits).to.be.bignumber.equal(0);
+            const expectedETHBalance = preETHBalance.add(depositWeiAmount).round(decimalPlaces);
+            gasCost = expectedETHBalance.minus(postETHBalance);
+            expect(gasCost).to.be.bignumber.lte(MAX_REASONABLE_GAS_COST_IN_WEI);
+        });
+        it('should throw if user has insufficient WETH balance for withdrawl', async () => {
+            const preWETHBalance = await zeroEx.token.getBalanceAsync(wethContractAddress, addressWithETH);
+            expect(preWETHBalance).to.be.bignumber.equal(0);
+
+            const overWETHBalance = preWETHBalance.add(999999999);
+
+            return expect(
+                zeroEx.etherToken.withdrawAsync(overWETHBalance, addressWithETH),
+            ).to.be.rejectedWith(ZeroExError.InsufficientWEthBalanceForWithdrawal);
+        });
+    });
+});
diff --git a/packages/0x.js/test/event_watcher_test.ts b/packages/0x.js/test/event_watcher_test.ts
new file mode 100644
index 000000000..b4164fe63
--- /dev/null
+++ b/packages/0x.js/test/event_watcher_test.ts
@@ -0,0 +1,127 @@
+import 'mocha';
+import * as chai from 'chai';
+import * as _ from 'lodash';
+import * as Sinon from 'sinon';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {chaiSetup} from './utils/chai_setup';
+import {web3Factory} from './utils/web3_factory';
+import {Web3Wrapper} from '../src/web3_wrapper';
+import {EventWatcher} from '../src/order_watcher/event_watcher';
+import {
+    ZeroEx,
+    LogEvent,
+    DecodedLogEvent,
+} from '../src';
+import {DoneCallback} from '../src/types';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+describe('EventWatcher', () => {
+    let web3: Web3;
+    let stubs: Sinon.SinonStub[] = [];
+    let eventWatcher: EventWatcher;
+    let web3Wrapper: Web3Wrapper;
+    const numConfirmations = 0;
+    const logA: Web3.LogEntry = {
+        address: '0x71d271f8b14adef568f8f28f1587ce7271ac4ca5',
+        blockHash: null,
+        blockNumber: null,
+        data: '',
+        logIndex: null,
+        topics: [],
+        transactionHash: '0x004881d38cd4a8f72f1a0d68c8b9b8124504706041ff37019c1d1ed6bfda8e17',
+        transactionIndex: 0,
+    };
+    const logB: Web3.LogEntry = {
+        address: '0x8d12a197cb00d4747a1fe03395095ce2a5cc6819',
+        blockHash: null,
+        blockNumber: null,
+        data: '',
+        logIndex: null,
+        topics: [ '0xf341246adaac6f497bc2a656f546ab9e182111d630394f0c57c710a59a2cb567' ],
+        transactionHash: '0x01ef3c048b18d9b09ea195b4ed94cf8dd5f3d857a1905ff886b152cfb1166f25',
+        transactionIndex: 0,
+    };
+    const logC: Web3.LogEntry = {
+        address: '0x1d271f8b174adef58f1587ce68f8f27271ac4ca5',
+        blockHash: null,
+        blockNumber: null,
+        data: '',
+        logIndex: null,
+        topics: [ '0xf341246adaac6f497bc2a656f546ab9e182111d630394f0c57c710a59a2cb567' ],
+        transactionHash: '0x01ef3c048b18d9b09ea195b4ed94cf8dd5f3d857a1905ff886b152cfb1166f25',
+        transactionIndex: 0,
+    };
+    before(async () => {
+        web3 = web3Factory.create();
+        const pollingIntervalMs = 10;
+        web3Wrapper = new Web3Wrapper(web3.currentProvider);
+        eventWatcher = new EventWatcher(web3Wrapper, pollingIntervalMs);
+    });
+    afterEach(() => {
+        // clean up any stubs after the test has completed
+        _.each(stubs, s => s.restore());
+        stubs = [];
+        eventWatcher.unsubscribe();
+    });
+    it('correctly emits initial log events', (done: DoneCallback) => {
+        const logs: Web3.LogEntry[] = [logA, logB];
+        const expectedLogEvents = [
+            {
+                removed: false,
+                ...logA,
+            },
+            {
+                removed: false,
+                ...logB,
+            },
+        ];
+        const getLogsStub = Sinon.stub(web3Wrapper, 'getLogsAsync');
+        getLogsStub.onCall(0).returns(logs);
+        stubs.push(getLogsStub);
+        const callback = (event: LogEvent) => {
+            const expectedLogEvent = expectedLogEvents.shift();
+            expect(event).to.be.deep.equal(expectedLogEvent);
+            if (_.isEmpty(expectedLogEvents)) {
+                done();
+            }
+        };
+        eventWatcher.subscribe(callback);
+    });
+    it('correctly computes the difference and emits only changes', (done: DoneCallback) => {
+        const initialLogs: Web3.LogEntry[] = [logA, logB];
+        const changedLogs: Web3.LogEntry[] = [logA, logC];
+        const expectedLogEvents = [
+            {
+                removed: false,
+                ...logA,
+            },
+            {
+                removed: false,
+                ...logB,
+            },
+            {
+                removed: true,
+                ...logB,
+            },
+            {
+                removed: false,
+                ...logC,
+            },
+        ];
+        const getLogsStub = Sinon.stub(web3Wrapper, 'getLogsAsync');
+        getLogsStub.onCall(0).returns(initialLogs);
+        getLogsStub.onCall(1).returns(changedLogs);
+        stubs.push(getLogsStub);
+        const callback = (event: LogEvent) => {
+            const expectedLogEvent = expectedLogEvents.shift();
+            expect(event).to.be.deep.equal(expectedLogEvent);
+            if (_.isEmpty(expectedLogEvents)) {
+                done();
+            }
+        };
+        eventWatcher.subscribe(callback);
+    });
+});
diff --git a/packages/0x.js/test/exchange_transfer_simulator_test.ts b/packages/0x.js/test/exchange_transfer_simulator_test.ts
new file mode 100644
index 000000000..99cb7fb4f
--- /dev/null
+++ b/packages/0x.js/test/exchange_transfer_simulator_test.ts
@@ -0,0 +1,87 @@
+import * as chai from 'chai';
+import BigNumber from 'bignumber.js';
+import {chaiSetup} from './utils/chai_setup';
+import {web3Factory} from './utils/web3_factory';
+import {ZeroEx, ExchangeContractErrs, Token} from '../src';
+import {TradeSide, TransferType} from '../src/types';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {ExchangeTransferSimulator} from '../src/utils/exchange_transfer_simulator';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+describe('ExchangeTransferSimulator', () => {
+    const web3 = web3Factory.create();
+    const zeroEx = new ZeroEx(web3.currentProvider);
+    const transferAmount = new BigNumber(5);
+    let userAddresses: string[];
+    let tokens: Token[];
+    let coinbase: string;
+    let sender: string;
+    let recipient: string;
+    let exampleTokenAddress: string;
+    let exchangeTransferSimulator: ExchangeTransferSimulator;
+    let txHash: string;
+    before(async () => {
+        userAddresses = await zeroEx.getAvailableAddressesAsync();
+        [coinbase, sender, recipient] = userAddresses;
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
+        exampleTokenAddress = tokens[0].address;
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('#transferFromAsync', () => {
+        beforeEach(() => {
+            exchangeTransferSimulator = new ExchangeTransferSimulator(zeroEx.token);
+        });
+        it('throws if the user doesn\'t have enough allowance', async () => {
+            return expect(exchangeTransferSimulator.transferFromAsync(
+                exampleTokenAddress, sender, recipient, transferAmount, TradeSide.Taker, TransferType.Trade,
+            )).to.be.rejectedWith(ExchangeContractErrs.InsufficientTakerAllowance);
+        });
+        it('throws if the user doesn\'t have enough balance', async () => {
+            txHash = await zeroEx.token.setProxyAllowanceAsync(exampleTokenAddress, sender, transferAmount);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            return expect(exchangeTransferSimulator.transferFromAsync(
+                exampleTokenAddress, sender, recipient, transferAmount, TradeSide.Maker, TransferType.Trade,
+            )).to.be.rejectedWith(ExchangeContractErrs.InsufficientMakerBalance);
+        });
+        it('updates balances and proxyAllowance after transfer', async () => {
+            txHash = await zeroEx.token.transferAsync(exampleTokenAddress, coinbase, sender, transferAmount);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            txHash = await zeroEx.token.setProxyAllowanceAsync(exampleTokenAddress, sender, transferAmount);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            await exchangeTransferSimulator.transferFromAsync(
+                exampleTokenAddress, sender, recipient, transferAmount, TradeSide.Taker, TransferType.Trade,
+            );
+            const store = (exchangeTransferSimulator as any).store;
+            const senderBalance = await store.getBalanceAsync(exampleTokenAddress, sender);
+            const recipientBalance = await store.getBalanceAsync(exampleTokenAddress, recipient);
+            const senderProxyAllowance = await store.getProxyAllowanceAsync(exampleTokenAddress, sender);
+            expect(senderBalance).to.be.bignumber.equal(0);
+            expect(recipientBalance).to.be.bignumber.equal(transferAmount);
+            expect(senderProxyAllowance).to.be.bignumber.equal(0);
+        });
+        it('doesn\'t update proxyAllowance after transfer if unlimited', async () => {
+            txHash = await zeroEx.token.transferAsync(exampleTokenAddress, coinbase, sender, transferAmount);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(exampleTokenAddress, sender);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            await exchangeTransferSimulator.transferFromAsync(
+                exampleTokenAddress, sender, recipient, transferAmount, TradeSide.Taker, TransferType.Trade,
+            );
+            const store = (exchangeTransferSimulator as any).store;
+            const senderBalance = await store.getBalanceAsync(exampleTokenAddress, sender);
+            const recipientBalance = await store.getBalanceAsync(exampleTokenAddress, recipient);
+            const senderProxyAllowance = await store.getProxyAllowanceAsync(exampleTokenAddress, sender);
+            expect(senderBalance).to.be.bignumber.equal(0);
+            expect(recipientBalance).to.be.bignumber.equal(transferAmount);
+            expect(senderProxyAllowance).to.be.bignumber.equal(zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+        });
+    });
+});
diff --git a/packages/0x.js/test/exchange_wrapper_test.ts b/packages/0x.js/test/exchange_wrapper_test.ts
new file mode 100644
index 000000000..26b8c1e0e
--- /dev/null
+++ b/packages/0x.js/test/exchange_wrapper_test.ts
@@ -0,0 +1,824 @@
+import 'mocha';
+import * as chai from 'chai';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import {chaiSetup} from './utils/chai_setup';
+import {web3Factory} from './utils/web3_factory';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {
+    ZeroEx,
+    Token,
+    SignedOrder,
+    SubscriptionOpts,
+    ExchangeEvents,
+    ExchangeContractErrs,
+    OrderCancellationRequest,
+    OrderFillRequest,
+    LogFillContractEventArgs,
+    LogCancelContractEventArgs,
+    LogEvent,
+    DecodedLogEvent,
+} from '../src';
+import {DoneCallback, BlockParamLiteral} from '../src/types';
+import {FillScenarios} from './utils/fill_scenarios';
+import {TokenUtils} from './utils/token_utils';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+const NON_EXISTENT_ORDER_HASH = '0x79370342234e7acd6bbeac335bd3bb1d368383294b64b8160a00f4060e4d3777';
+
+describe('ExchangeWrapper', () => {
+    let web3: Web3;
+    let zeroEx: ZeroEx;
+    let tokenUtils: TokenUtils;
+    let tokens: Token[];
+    let userAddresses: string[];
+    let zrxTokenAddress: string;
+    let fillScenarios: FillScenarios;
+    let exchangeContractAddress: string;
+    before(async () => {
+        web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider);
+        exchangeContractAddress = await zeroEx.exchange.getContractAddressAsync();
+        userAddresses = await zeroEx.getAvailableAddressesAsync();
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
+        tokenUtils = new TokenUtils(tokens);
+        zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
+        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress, exchangeContractAddress);
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('fillOrKill order(s)', () => {
+        let makerTokenAddress: string;
+        let takerTokenAddress: string;
+        let coinbase: string;
+        let makerAddress: string;
+        let takerAddress: string;
+        let feeRecipient: string;
+        const takerTokenFillAmount = new BigNumber(5);
+        before(async () => {
+            [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
+            tokens = await zeroEx.tokenRegistry.getTokensAsync();
+            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+        });
+        describe('#batchFillOrKillAsync', () => {
+            it('successfully batch fillOrKill', async () => {
+                const fillableAmount = new BigNumber(5);
+                const partialFillTakerAmount = new BigNumber(2);
+                const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+                const anotherSignedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+                const orderFillRequests = [
+                    {
+                        signedOrder,
+                        takerTokenFillAmount: partialFillTakerAmount,
+                    },
+                    {
+                        signedOrder: anotherSignedOrder,
+                        takerTokenFillAmount: partialFillTakerAmount,
+                    },
+                ];
+                await zeroEx.exchange.batchFillOrKillAsync(orderFillRequests, takerAddress);
+            });
+            describe('order transaction options', () => {
+                let signedOrder: SignedOrder;
+                let orderFillRequests: OrderFillRequest[];
+                const fillableAmount = new BigNumber(5);
+                beforeEach(async () => {
+                    signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                        makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                    );
+                    orderFillRequests = [
+                        {
+                            signedOrder,
+                            takerTokenFillAmount: new BigNumber(0),
+                        },
+                    ];
+                });
+                it('should validate when orderTransactionOptions are not present', async () => {
+                    return expect(zeroEx.exchange.batchFillOrKillAsync(orderFillRequests, takerAddress))
+                        .to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should validate when orderTransactionOptions specify to validate', async () => {
+                    return expect(zeroEx.exchange.batchFillOrKillAsync(orderFillRequests, takerAddress, {
+                        shouldValidate: true,
+                    })).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should not validate when orderTransactionOptions specify not to validate', async () => {
+                    return expect(zeroEx.exchange.batchFillOrKillAsync(orderFillRequests, takerAddress, {
+                        shouldValidate: false,
+                    })).to.not.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+            });
+        });
+        describe('#fillOrKillOrderAsync', () => {
+            let signedOrder: SignedOrder;
+            const fillableAmount = new BigNumber(5);
+            beforeEach(async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+            });
+            describe('successful fills', () => {
+                it('should fill a valid order', async () => {
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(fillableAmount);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(0);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(0);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(fillableAmount);
+                    await zeroEx.exchange.fillOrKillOrderAsync(signedOrder, takerTokenFillAmount, takerAddress);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(takerTokenFillAmount));
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(takerTokenFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(takerTokenFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(takerTokenFillAmount));
+                });
+                it('should partially fill a valid order', async () => {
+                    const partialFillAmount = new BigNumber(3);
+                    await zeroEx.exchange.fillOrKillOrderAsync(signedOrder, partialFillAmount, takerAddress);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(partialFillAmount));
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(partialFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(partialFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(partialFillAmount));
+                });
+            });
+            describe('order transaction options', () => {
+                const emptyFillableAmount = new BigNumber(0);
+                it('should validate when orderTransactionOptions are not present', async () => {
+                    return expect(zeroEx.exchange.fillOrKillOrderAsync(signedOrder, emptyFillableAmount, takerAddress))
+                        .to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should validate when orderTransactionOptions specify to validate', async () => {
+                    return expect(zeroEx.exchange.fillOrKillOrderAsync(signedOrder, emptyFillableAmount, takerAddress, {
+                        shouldValidate: true,
+                    })).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should not validate when orderTransactionOptions specify not to validate', async () => {
+                    return expect(zeroEx.exchange.fillOrKillOrderAsync(signedOrder, emptyFillableAmount, takerAddress, {
+                        shouldValidate: false,
+                    })).to.not.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+            });
+        });
+    });
+    describe('fill order(s)', () => {
+        let makerTokenAddress: string;
+        let takerTokenAddress: string;
+        let coinbase: string;
+        let makerAddress: string;
+        let takerAddress: string;
+        let feeRecipient: string;
+        const fillableAmount = new BigNumber(5);
+        const takerTokenFillAmount = new BigNumber(5);
+        const shouldThrowOnInsufficientBalanceOrAllowance = true;
+        before(async () => {
+            [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
+            tokens = await zeroEx.tokenRegistry.getTokensAsync();
+            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+        });
+        describe('#fillOrderAsync', () => {
+            describe('successful fills', () => {
+                it('should fill a valid order', async () => {
+                    const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                        makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                    );
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(fillableAmount);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(0);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(0);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(fillableAmount);
+                    const txHash = await zeroEx.exchange.fillOrderAsync(
+                        signedOrder, takerTokenFillAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress);
+                    await zeroEx.awaitTransactionMinedAsync(txHash);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(takerTokenFillAmount));
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(takerTokenFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(takerTokenFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(takerTokenFillAmount));
+                });
+                it('should partially fill the valid order', async () => {
+                    const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                        makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                    );
+                    const partialFillAmount = new BigNumber(3);
+                    const txHash = await zeroEx.exchange.fillOrderAsync(
+                        signedOrder, partialFillAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress);
+                    await zeroEx.awaitTransactionMinedAsync(txHash);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(partialFillAmount));
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, makerAddress))
+                        .to.be.bignumber.equal(partialFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(makerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(partialFillAmount);
+                    expect(await zeroEx.token.getBalanceAsync(takerTokenAddress, takerAddress))
+                        .to.be.bignumber.equal(fillableAmount.minus(partialFillAmount));
+                });
+                it('should fill the valid orders with fees', async () => {
+                    const makerFee = new BigNumber(1);
+                    const takerFee = new BigNumber(2);
+                    const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                        makerTokenAddress, takerTokenAddress, makerFee, takerFee,
+                        makerAddress, takerAddress, fillableAmount, feeRecipient,
+                    );
+                    const txHash = await zeroEx.exchange.fillOrderAsync(
+                        signedOrder, takerTokenFillAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress);
+                    await zeroEx.awaitTransactionMinedAsync(txHash);
+                    expect(await zeroEx.token.getBalanceAsync(zrxTokenAddress, feeRecipient))
+                        .to.be.bignumber.equal(makerFee.plus(takerFee));
+                });
+            });
+            describe('order transaction options', () => {
+                let signedOrder: SignedOrder;
+                const emptyFillTakerAmount = new BigNumber(0);
+                beforeEach(async () => {
+                    signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                        makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                    );
+                });
+                it('should validate when orderTransactionOptions are not present', async () => {
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, emptyFillTakerAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+                    )).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should validate when orderTransactionOptions specify to validate', async () => {
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, emptyFillTakerAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress, {
+                            shouldValidate: true,
+                    })).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should not validate when orderTransactionOptions specify not to validate', async () => {
+                    return expect(zeroEx.exchange.fillOrderAsync(
+                        signedOrder, emptyFillTakerAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress, {
+                            shouldValidate: false,
+                    })).to.not.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+            });
+        });
+        describe('#batchFillOrdersAsync', () => {
+            let signedOrder: SignedOrder;
+            let signedOrderHashHex: string;
+            let anotherSignedOrder: SignedOrder;
+            let anotherOrderHashHex: string;
+            let orderFillBatch: OrderFillRequest[];
+            beforeEach(async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+                signedOrderHashHex = ZeroEx.getOrderHashHex(signedOrder);
+                anotherSignedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+                anotherOrderHashHex = ZeroEx.getOrderHashHex(anotherSignedOrder);
+            });
+            describe('successful batch fills', () => {
+                beforeEach(() => {
+                    orderFillBatch = [
+                        {
+                            signedOrder,
+                            takerTokenFillAmount,
+                        },
+                        {
+                            signedOrder: anotherSignedOrder,
+                            takerTokenFillAmount,
+                        },
+                    ];
+                });
+                it('should throw if a batch is empty', async () => {
+                    return expect(zeroEx.exchange.batchFillOrdersAsync(
+                        [], shouldThrowOnInsufficientBalanceOrAllowance, takerAddress),
+                    ).to.be.rejectedWith(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
+                });
+                it('should successfully fill multiple orders', async () => {
+                    const txHash = await zeroEx.exchange.batchFillOrdersAsync(
+                        orderFillBatch, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress);
+                    await zeroEx.awaitTransactionMinedAsync(txHash);
+                    const filledAmount = await zeroEx.exchange.getFilledTakerAmountAsync(signedOrderHashHex);
+                    const anotherFilledAmount = await zeroEx.exchange.getFilledTakerAmountAsync(anotherOrderHashHex);
+                    expect(filledAmount).to.be.bignumber.equal(takerTokenFillAmount);
+                    expect(anotherFilledAmount).to.be.bignumber.equal(takerTokenFillAmount);
+                });
+            });
+            describe('order transaction options', () => {
+                beforeEach(async () => {
+                    const emptyFillTakerAmount = new BigNumber(0);
+                    orderFillBatch = [
+                        {
+                            signedOrder,
+                            takerTokenFillAmount: emptyFillTakerAmount,
+                        },
+                        {
+                            signedOrder: anotherSignedOrder,
+                            takerTokenFillAmount: emptyFillTakerAmount,
+                        },
+                    ];
+                });
+                it('should validate when orderTransactionOptions are not present', async () => {
+                    return expect(zeroEx.exchange.batchFillOrdersAsync(
+                        orderFillBatch, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress),
+                    ).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should validate when orderTransactionOptions specify to validate', async () => {
+                    return expect(zeroEx.exchange.batchFillOrdersAsync(
+                        orderFillBatch, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress, {
+                            shouldValidate: true,
+                    })).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should not validate when orderTransactionOptions specify not to validate', async () => {
+                    return expect(zeroEx.exchange.batchFillOrdersAsync(
+                        orderFillBatch, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress, {
+                            shouldValidate: false,
+                    })).to.not.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+            });
+        });
+        describe('#fillOrdersUpTo', () => {
+            let signedOrder: SignedOrder;
+            let signedOrderHashHex: string;
+            let anotherSignedOrder: SignedOrder;
+            let anotherOrderHashHex: string;
+            let signedOrders: SignedOrder[];
+            const fillUpToAmount = fillableAmount.plus(fillableAmount).minus(1);
+            beforeEach(async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+                signedOrderHashHex = ZeroEx.getOrderHashHex(signedOrder);
+                anotherSignedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+                anotherOrderHashHex = ZeroEx.getOrderHashHex(anotherSignedOrder);
+                signedOrders = [signedOrder, anotherSignedOrder];
+            });
+            describe('successful batch fills', () => {
+                it('should throw if a batch is empty', async () => {
+                    return expect(zeroEx.exchange.fillOrdersUpToAsync(
+                        [], fillUpToAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress),
+                    ).to.be.rejectedWith(ExchangeContractErrs.BatchOrdersMustHaveAtLeastOneItem);
+                });
+                it('should successfully fill up to specified amount', async () => {
+                    const txHash = await zeroEx.exchange.fillOrdersUpToAsync(
+                        signedOrders, fillUpToAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+                    );
+                    await zeroEx.awaitTransactionMinedAsync(txHash);
+                    const filledAmount = await zeroEx.exchange.getFilledTakerAmountAsync(signedOrderHashHex);
+                    const anotherFilledAmount = await zeroEx.exchange.getFilledTakerAmountAsync(anotherOrderHashHex);
+                    expect(filledAmount).to.be.bignumber.equal(fillableAmount);
+                    const remainingFillAmount = fillableAmount.minus(1);
+                    expect(anotherFilledAmount).to.be.bignumber.equal(remainingFillAmount);
+                });
+            });
+            describe('order transaction options', () => {
+                const emptyFillUpToAmount = new BigNumber(0);
+                it('should validate when orderTransactionOptions are not present', async () => {
+                    return expect(zeroEx.exchange.fillOrdersUpToAsync(
+                        signedOrders, emptyFillUpToAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+                    )).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should validate when orderTransactionOptions specify to validate', async () => {
+                    return expect(zeroEx.exchange.fillOrdersUpToAsync(
+                        signedOrders, emptyFillUpToAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress, {
+                            shouldValidate: true,
+                    })).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+                it('should not validate when orderTransactionOptions specify not to validate', async () => {
+                    return expect(zeroEx.exchange.fillOrdersUpToAsync(
+                        signedOrders, emptyFillUpToAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress, {
+                            shouldValidate: false,
+                    })).to.not.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+                });
+            });
+        });
+    });
+    describe('cancel order(s)', () => {
+        let makerTokenAddress: string;
+        let takerTokenAddress: string;
+        let coinbase: string;
+        let makerAddress: string;
+        let takerAddress: string;
+        const fillableAmount = new BigNumber(5);
+        let signedOrder: SignedOrder;
+        let orderHashHex: string;
+        const cancelAmount = new BigNumber(3);
+        beforeEach(async () => {
+            [coinbase, makerAddress, takerAddress] = userAddresses;
+            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            orderHashHex = ZeroEx.getOrderHashHex(signedOrder);
+        });
+        describe('#cancelOrderAsync', () => {
+            describe('successful cancels', () => {
+                it('should cancel an order', async () => {
+                    const txHash = await zeroEx.exchange.cancelOrderAsync(signedOrder, cancelAmount);
+                    await zeroEx.awaitTransactionMinedAsync(txHash);
+                    const cancelledAmount = await zeroEx.exchange.getCanceledTakerAmountAsync(orderHashHex);
+                    expect(cancelledAmount).to.be.bignumber.equal(cancelAmount);
+                });
+            });
+            describe('order transaction options', () => {
+                const emptyCancelTakerTokenAmount = new BigNumber(0);
+                it('should validate when orderTransactionOptions are not present', async () => {
+                    return expect(zeroEx.exchange.cancelOrderAsync(signedOrder, emptyCancelTakerTokenAmount))
+                        .to.be.rejectedWith(ExchangeContractErrs.OrderCancelAmountZero);
+                });
+                it('should validate when orderTransactionOptions specify to validate', async () => {
+                    return expect(zeroEx.exchange.cancelOrderAsync(signedOrder, emptyCancelTakerTokenAmount, {
+                        shouldValidate: true,
+                    })).to.be.rejectedWith(ExchangeContractErrs.OrderCancelAmountZero);
+                });
+                it('should not validate when orderTransactionOptions specify not to validate', async () => {
+                    return expect(zeroEx.exchange.cancelOrderAsync(signedOrder, emptyCancelTakerTokenAmount, {
+                        shouldValidate: false,
+                    })).to.not.be.rejectedWith(ExchangeContractErrs.OrderCancelAmountZero);
+                });
+            });
+        });
+        describe('#batchCancelOrdersAsync', () => {
+            let anotherSignedOrder: SignedOrder;
+            let anotherOrderHashHex: string;
+            let cancelBatch: OrderCancellationRequest[];
+            beforeEach(async () => {
+                anotherSignedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+                );
+                anotherOrderHashHex = ZeroEx.getOrderHashHex(anotherSignedOrder);
+                cancelBatch = [
+                    {
+                        order: signedOrder,
+                        takerTokenCancelAmount: cancelAmount,
+                    },
+                    {
+                        order: anotherSignedOrder,
+                        takerTokenCancelAmount: cancelAmount,
+                    },
+                ];
+            });
+            describe('failed batch cancels', () => {
+                it('should throw when orders have different makers', async () => {
+                    const signedOrderWithDifferentMaker = await fillScenarios.createFillableSignedOrderAsync(
+                        makerTokenAddress, takerTokenAddress, takerAddress, takerAddress, fillableAmount,
+                    );
+                    return expect(zeroEx.exchange.batchCancelOrdersAsync([
+                        cancelBatch[0],
+                        {
+                            order: signedOrderWithDifferentMaker,
+                            takerTokenCancelAmount: cancelAmount,
+                        },
+                    ])).to.be.rejectedWith(ExchangeContractErrs.MultipleMakersInSingleCancelBatchDisallowed);
+                });
+            });
+            describe('successful batch cancels', () => {
+                it('should cancel a batch of orders', async () => {
+                    await zeroEx.exchange.batchCancelOrdersAsync(cancelBatch);
+                    const cancelledAmount = await zeroEx.exchange.getCanceledTakerAmountAsync(orderHashHex);
+                    const anotherCancelledAmount = await zeroEx.exchange.getCanceledTakerAmountAsync(
+                        anotherOrderHashHex,
+                    );
+                    expect(cancelledAmount).to.be.bignumber.equal(cancelAmount);
+                    expect(anotherCancelledAmount).to.be.bignumber.equal(cancelAmount);
+                });
+            });
+            describe('order transaction options', () => {
+                beforeEach(async () => {
+                    const emptyTakerTokenCancelAmount = new BigNumber(0);
+                    cancelBatch = [
+                        {
+                            order: signedOrder,
+                            takerTokenCancelAmount: emptyTakerTokenCancelAmount,
+                        },
+                        {
+                            order: anotherSignedOrder,
+                            takerTokenCancelAmount: emptyTakerTokenCancelAmount,
+                        },
+                    ];
+                });
+                it('should validate when orderTransactionOptions are not present', async () => {
+                    return expect(zeroEx.exchange.batchCancelOrdersAsync(cancelBatch))
+                        .to.be.rejectedWith(ExchangeContractErrs.OrderCancelAmountZero);
+                });
+                it('should validate when orderTransactionOptions specify to validate', async () => {
+                    return expect(zeroEx.exchange.batchCancelOrdersAsync(cancelBatch, {
+                        shouldValidate: true,
+                    })).to.be.rejectedWith(ExchangeContractErrs.OrderCancelAmountZero);
+                });
+                it('should not validate when orderTransactionOptions specify not to validate', async () => {
+                    return expect(zeroEx.exchange.batchCancelOrdersAsync(cancelBatch, {
+                        shouldValidate: false,
+                    })).to.not.be.rejectedWith(ExchangeContractErrs.OrderCancelAmountZero);
+                });
+            });
+        });
+    });
+    describe('tests that require partially filled order', () => {
+        let makerTokenAddress: string;
+        let takerTokenAddress: string;
+        let takerAddress: string;
+        let fillableAmount: BigNumber;
+        let partialFillAmount: BigNumber;
+        let signedOrder: SignedOrder;
+        let orderHash: string;
+        before(() => {
+            takerAddress = userAddresses[1];
+            const [makerToken, takerToken] = tokens;
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+        });
+        beforeEach(async () => {
+            fillableAmount = new BigNumber(5);
+            partialFillAmount = new BigNumber(2);
+            signedOrder = await fillScenarios.createPartiallyFilledSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, takerAddress, fillableAmount, partialFillAmount,
+            );
+            orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        });
+        describe('#getUnavailableTakerAmountAsync', () => {
+            it('should throw if passed an invalid orderHash', async () => {
+                const invalidOrderHashHex = '0x123';
+                return expect(zeroEx.exchange.getUnavailableTakerAmountAsync(invalidOrderHashHex)).to.be.rejected();
+            });
+            it('should return zero if passed a valid but non-existent orderHash', async () => {
+                const unavailableValueT = await zeroEx.exchange.getUnavailableTakerAmountAsync(NON_EXISTENT_ORDER_HASH);
+                expect(unavailableValueT).to.be.bignumber.equal(0);
+            });
+            it('should return the unavailableValueT for a valid and partially filled orderHash', async () => {
+                const unavailableValueT = await zeroEx.exchange.getUnavailableTakerAmountAsync(orderHash);
+                expect(unavailableValueT).to.be.bignumber.equal(partialFillAmount);
+            });
+        });
+        describe('#getFilledTakerAmountAsync', () => {
+            it('should throw if passed an invalid orderHash', async () => {
+                const invalidOrderHashHex = '0x123';
+                return expect(zeroEx.exchange.getFilledTakerAmountAsync(invalidOrderHashHex)).to.be.rejected();
+            });
+            it('should return zero if passed a valid but non-existent orderHash', async () => {
+                const filledValueT = await zeroEx.exchange.getFilledTakerAmountAsync(NON_EXISTENT_ORDER_HASH,
+                );
+                expect(filledValueT).to.be.bignumber.equal(0);
+            });
+            it('should return the filledValueT for a valid and partially filled orderHash', async () => {
+                const filledValueT = await zeroEx.exchange.getFilledTakerAmountAsync(orderHash);
+                expect(filledValueT).to.be.bignumber.equal(partialFillAmount);
+            });
+        });
+        describe('#getCanceledTakerAmountAsync', () => {
+            it('should throw if passed an invalid orderHash', async () => {
+                const invalidOrderHashHex = '0x123';
+                return expect(zeroEx.exchange.getCanceledTakerAmountAsync(invalidOrderHashHex)).to.be.rejected();
+            });
+            it('should return zero if passed a valid but non-existent orderHash', async () => {
+                const cancelledValueT = await zeroEx.exchange.getCanceledTakerAmountAsync(NON_EXISTENT_ORDER_HASH);
+                expect(cancelledValueT).to.be.bignumber.equal(0);
+            });
+            it('should return the cancelledValueT for a valid and partially filled orderHash', async () => {
+                const cancelledValueT = await zeroEx.exchange.getCanceledTakerAmountAsync(orderHash);
+                expect(cancelledValueT).to.be.bignumber.equal(0);
+            });
+            it('should return the cancelledValueT for a valid and cancelled orderHash', async () => {
+                const cancelAmount = fillableAmount.minus(partialFillAmount);
+                await zeroEx.exchange.cancelOrderAsync(signedOrder, cancelAmount);
+                const cancelledValueT = await zeroEx.exchange.getCanceledTakerAmountAsync(orderHash);
+                expect(cancelledValueT).to.be.bignumber.equal(cancelAmount);
+            });
+        });
+    });
+    describe('#subscribeAsync', () => {
+        const indexFilterValues = {};
+        const shouldThrowOnInsufficientBalanceOrAllowance = true;
+        let makerTokenAddress: string;
+        let takerTokenAddress: string;
+        let coinbase: string;
+        let takerAddress: string;
+        let makerAddress: string;
+        let fillableAmount: BigNumber;
+        let signedOrder: SignedOrder;
+        const takerTokenFillAmountInBaseUnits = new BigNumber(1);
+        const cancelTakerAmountInBaseUnits = new BigNumber(1);
+        before(() => {
+            [coinbase, makerAddress, takerAddress] = userAddresses;
+            const [makerToken, takerToken] = tokens;
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+        });
+        beforeEach(async () => {
+            fillableAmount = new BigNumber(5);
+            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+        });
+        afterEach(async () => {
+            zeroEx.exchange.unsubscribeAll();
+        });
+        // Hack: Mocha does not allow a test to be both async and have a `done` callback
+        // Since we need to await the receipt of the event in the `subscribe` callback,
+        // we do need both. A hack is to make the top-level a sync fn w/ a done callback and then
+        // wrap the rest of the test in an async block
+        // Source: https://github.com/mochajs/mocha/issues/2407
+        it('Should receive the LogFill event when an order is filled', (done: DoneCallback) => {
+            (async () => {
+
+                const callback = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                    expect(logEvent.event).to.be.equal(ExchangeEvents.LogFill);
+                    done();
+                };
+                await zeroEx.exchange.subscribeAsync(
+                    ExchangeEvents.LogFill, indexFilterValues, callback,
+                );
+                await zeroEx.exchange.fillOrderAsync(
+                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance,
+                    takerAddress,
+                );
+            })().catch(done);
+        });
+        it('Should receive the LogCancel event when an order is cancelled', (done: DoneCallback) => {
+            (async () => {
+
+                const callback = (err: Error, logEvent: DecodedLogEvent<LogCancelContractEventArgs>) => {
+                    expect(logEvent.event).to.be.equal(ExchangeEvents.LogCancel);
+                    done();
+                };
+                await zeroEx.exchange.subscribeAsync(
+                    ExchangeEvents.LogCancel, indexFilterValues, callback,
+                );
+                await zeroEx.exchange.cancelOrderAsync(signedOrder, cancelTakerAmountInBaseUnits);
+            })().catch(done);
+        });
+        it('Outstanding subscriptions are cancelled when zeroEx.setProviderAsync called', (done: DoneCallback) => {
+            (async () => {
+
+                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                    done(new Error('Expected this subscription to have been cancelled'));
+                };
+                await zeroEx.exchange.subscribeAsync(
+                    ExchangeEvents.LogFill, indexFilterValues, callbackNeverToBeCalled,
+                );
+
+                const newProvider = web3Factory.getRpcProvider();
+                await zeroEx.setProviderAsync(newProvider);
+
+                const callback = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                    expect(logEvent.event).to.be.equal(ExchangeEvents.LogFill);
+                    done();
+                };
+                await zeroEx.exchange.subscribeAsync(
+                    ExchangeEvents.LogFill, indexFilterValues, callback,
+                );
+                await zeroEx.exchange.fillOrderAsync(
+                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance,
+                    takerAddress,
+                );
+            })().catch(done);
+        });
+        it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
+            (async () => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
+                    done(new Error('Expected this subscription to have been cancelled'));
+                };
+                const subscriptionToken = await zeroEx.exchange.subscribeAsync(
+                    ExchangeEvents.LogFill, indexFilterValues, callbackNeverToBeCalled,
+                );
+                zeroEx.exchange.unsubscribe(subscriptionToken);
+                await zeroEx.exchange.fillOrderAsync(
+                    signedOrder, takerTokenFillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance,
+                    takerAddress,
+                );
+                done();
+            })().catch(done);
+        });
+    });
+    describe('#getOrderHashHexUsingContractCallAsync', () => {
+        let makerTokenAddress: string;
+        let takerTokenAddress: string;
+        let makerAddress: string;
+        let takerAddress: string;
+        const fillableAmount = new BigNumber(5);
+        before(async () => {
+            [, makerAddress, takerAddress] = userAddresses;
+            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+        });
+        it('get\'s the same hash as the local function', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+            const orderHashFromContract = await (zeroEx.exchange as any)
+                ._getOrderHashHexUsingContractCallAsync(signedOrder);
+            expect(orderHash).to.equal(orderHashFromContract);
+        });
+    });
+    describe('#getZRXTokenAddressAsync', () => {
+        it('gets the same token as is in token registry', async () => {
+            const zrxAddress = await zeroEx.exchange.getZRXTokenAddressAsync();
+            const zrxToken = tokenUtils.getProtocolTokenOrThrow();
+            expect(zrxAddress).to.equal(zrxToken.address);
+        });
+    });
+    describe('#getLogsAsync', () => {
+        let makerTokenAddress: string;
+        let takerTokenAddress: string;
+        let makerAddress: string;
+        let takerAddress: string;
+        const fillableAmount = new BigNumber(5);
+        const shouldThrowOnInsufficientBalanceOrAllowance = true;
+        const subscriptionOpts: SubscriptionOpts = {
+            fromBlock: BlockParamLiteral.Earliest,
+            toBlock: BlockParamLiteral.Latest,
+        };
+        let txHash: string;
+        before(async () => {
+            [, makerAddress, takerAddress] = userAddresses;
+            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+        });
+        it('should get logs with decoded args emitted by LogFill', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            txHash = await zeroEx.exchange.fillOrderAsync(
+                signedOrder, fillableAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+            );
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const eventName = ExchangeEvents.LogFill;
+            const indexFilterValues = {};
+            const logs = await zeroEx.exchange.getLogsAsync(eventName, subscriptionOpts, indexFilterValues);
+            expect(logs).to.have.length(1);
+            expect(logs[0].event).to.be.equal(eventName);
+        });
+        it('should only get the logs with the correct event name', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            txHash = await zeroEx.exchange.fillOrderAsync(
+                signedOrder, fillableAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+            );
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const differentEventName = ExchangeEvents.LogCancel;
+            const indexFilterValues = {};
+            const logs = await zeroEx.exchange.getLogsAsync(differentEventName, subscriptionOpts, indexFilterValues);
+            expect(logs).to.have.length(0);
+        });
+        it('should only get the logs with the correct indexed fields', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            txHash = await zeroEx.exchange.fillOrderAsync(
+                signedOrder, fillableAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+            );
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+
+            const differentMakerAddress = userAddresses[2];
+            const anotherSignedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, differentMakerAddress, takerAddress, fillableAmount,
+            );
+            txHash = await zeroEx.exchange.fillOrderAsync(
+                anotherSignedOrder, fillableAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+            );
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+
+            const eventName = ExchangeEvents.LogFill;
+            const indexFilterValues = {
+                maker: differentMakerAddress,
+            };
+            const logs = await zeroEx.exchange.getLogsAsync<LogFillContractEventArgs>(
+                eventName, subscriptionOpts, indexFilterValues,
+            );
+            expect(logs).to.have.length(1);
+            const args = logs[0].args;
+            expect(args.maker).to.be.equal(differentMakerAddress);
+        });
+    });
+});
diff --git a/packages/0x.js/test/order_state_watcher_test.ts b/packages/0x.js/test/order_state_watcher_test.ts
new file mode 100644
index 000000000..c8a4a8064
--- /dev/null
+++ b/packages/0x.js/test/order_state_watcher_test.ts
@@ -0,0 +1,356 @@
+import 'mocha';
+import * as chai from 'chai';
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import { chaiSetup } from './utils/chai_setup';
+import { web3Factory } from './utils/web3_factory';
+import { Web3Wrapper } from '../src/web3_wrapper';
+import { OrderStateWatcher } from '../src/order_watcher/order_state_watcher';
+import {
+    Token,
+    ZeroEx,
+    LogEvent,
+    DecodedLogEvent,
+    ZeroExConfig,
+    OrderState,
+    SignedOrder,
+    ZeroExError,
+    OrderStateValid,
+    OrderStateInvalid,
+    ExchangeContractErrs,
+} from '../src';
+import { TokenUtils } from './utils/token_utils';
+import { FillScenarios } from './utils/fill_scenarios';
+import { DoneCallback } from '../src/types';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {reportCallbackErrors} from './utils/report_callback_errors';
+
+const TIMEOUT_MS = 150;
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+describe('OrderStateWatcher', () => {
+    let web3: Web3;
+    let zeroEx: ZeroEx;
+    let tokens: Token[];
+    let tokenUtils: TokenUtils;
+    let fillScenarios: FillScenarios;
+    let userAddresses: string[];
+    let zrxTokenAddress: string;
+    let exchangeContractAddress: string;
+    let makerToken: Token;
+    let takerToken: Token;
+    let maker: string;
+    let taker: string;
+    let web3Wrapper: Web3Wrapper;
+    let signedOrder: SignedOrder;
+    const fillableAmount = new BigNumber(5);
+    before(async () => {
+        web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider);
+        exchangeContractAddress = await zeroEx.exchange.getContractAddressAsync();
+        userAddresses = await zeroEx.getAvailableAddressesAsync();
+        [, maker, taker] = userAddresses;
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
+        tokenUtils = new TokenUtils(tokens);
+        zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
+        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress, exchangeContractAddress);
+        [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+        web3Wrapper = (zeroEx as any)._web3Wrapper;
+    });
+    describe('#removeOrder', async () => {
+        it('should successfully remove existing order', async () => {
+            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerToken.address, takerToken.address, maker, taker, fillableAmount,
+            );
+            const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+            zeroEx.orderStateWatcher.addOrder(signedOrder);
+            expect((zeroEx.orderStateWatcher as any)._orderByOrderHash).to.include({
+                [orderHash]: signedOrder,
+            });
+            let dependentOrderHashes = (zeroEx.orderStateWatcher as any)._dependentOrderHashes;
+            expect(dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress]).to.have.keys(orderHash);
+            zeroEx.orderStateWatcher.removeOrder(orderHash);
+            expect((zeroEx.orderStateWatcher as any)._orderByOrderHash).to.not.include({
+                [orderHash]: signedOrder,
+            });
+            dependentOrderHashes = (zeroEx.orderStateWatcher as any)._dependentOrderHashes;
+            expect(dependentOrderHashes[signedOrder.maker]).to.be.undefined();
+        });
+        it('should no-op when removing a non-existing order', async () => {
+            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerToken.address, takerToken.address, maker, taker, fillableAmount,
+            );
+            const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+            const nonExistentOrderHash = `0x${orderHash.substr(2).split('').reverse().join('')}`;
+            zeroEx.orderStateWatcher.removeOrder(nonExistentOrderHash);
+        });
+    });
+    describe('#subscribe', async () => {
+        afterEach(async () => {
+            zeroEx.orderStateWatcher.unsubscribe();
+        });
+        it('should fail when trying to subscribe twice', async () => {
+            zeroEx.orderStateWatcher.subscribe(_.noop);
+            expect(() => zeroEx.orderStateWatcher.subscribe(_.noop))
+                .to.throw(ZeroExError.SubscriptionAlreadyPresent);
+        });
+    });
+    describe('tests with cleanup', async () => {
+        afterEach(async () => {
+            zeroEx.orderStateWatcher.unsubscribe();
+            const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+            zeroEx.orderStateWatcher.removeOrder(orderHash);
+        });
+        it('should emit orderStateInvalid when maker allowance set to 0 for watched order', (done: DoneCallback) => {
+            (async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                );
+                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
+                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    expect(orderState.isValid).to.be.false();
+                    const invalidOrderState = orderState as OrderStateInvalid;
+                    expect(invalidOrderState.orderHash).to.be.equal(orderHash);
+                    expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.InsufficientMakerAllowance);
+                    done();
+                });
+                zeroEx.orderStateWatcher.subscribe(callback);
+                await zeroEx.token.setProxyAllowanceAsync(makerToken.address, maker, new BigNumber(0));
+            })().catch(done);
+        });
+        it('should not emit an orderState event when irrelevant Transfer event received', (done: DoneCallback) => {
+            (async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                );
+                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
+                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    throw new Error('OrderState callback fired for irrelevant order');
+                });
+                zeroEx.orderStateWatcher.subscribe(callback);
+                const notTheMaker = userAddresses[0];
+                const anyRecipient = taker;
+                const transferAmount = new BigNumber(2);
+                const notTheMakerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, notTheMaker);
+                await zeroEx.token.transferAsync(makerToken.address, notTheMaker, anyRecipient, transferAmount);
+                setTimeout(() => {
+                    done();
+                }, TIMEOUT_MS);
+            })().catch(done);
+        });
+        it('should emit orderStateInvalid when maker moves balance backing watched order', (done: DoneCallback) => {
+            (async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                );
+                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
+                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    expect(orderState.isValid).to.be.false();
+                    const invalidOrderState = orderState as OrderStateInvalid;
+                    expect(invalidOrderState.orderHash).to.be.equal(orderHash);
+                    expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.InsufficientMakerBalance);
+                    done();
+                });
+                zeroEx.orderStateWatcher.subscribe(callback);
+                const anyRecipient = taker;
+                const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
+                await zeroEx.token.transferAsync(makerToken.address, maker, anyRecipient, makerBalance);
+            })().catch(done);
+        });
+        it('should emit orderStateInvalid when watched order fully filled', (done: DoneCallback) => {
+            (async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                );
+                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                let eventCount = 0;
+                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    eventCount++;
+                    expect(orderState.isValid).to.be.false();
+                    const invalidOrderState = orderState as OrderStateInvalid;
+                    expect(invalidOrderState.orderHash).to.be.equal(orderHash);
+                    expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.OrderRemainingFillAmountZero);
+                    if (eventCount === 2) {
+                        done();
+                    }
+                });
+                zeroEx.orderStateWatcher.subscribe(callback);
+
+                const shouldThrowOnInsufficientBalanceOrAllowance = true;
+                await zeroEx.exchange.fillOrderAsync(
+                    signedOrder, fillableAmount, shouldThrowOnInsufficientBalanceOrAllowance, taker,
+                );
+            })().catch(done);
+        });
+        it('should emit orderStateValid when watched order partially filled', (done: DoneCallback) => {
+            (async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                );
+
+                const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
+                const takerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, taker);
+
+                const fillAmountInBaseUnits = new BigNumber(2);
+                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                let eventCount = 0;
+                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    eventCount++;
+                    expect(orderState.isValid).to.be.true();
+                    const validOrderState = orderState as OrderStateValid;
+                    expect(validOrderState.orderHash).to.be.equal(orderHash);
+                    const orderRelevantState = validOrderState.orderRelevantState;
+                    const remainingMakerBalance = makerBalance.sub(fillAmountInBaseUnits);
+                    const remainingFillable = fillableAmount.minus(fillAmountInBaseUnits);
+                    expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
+                        remainingFillable);
+                    expect(orderRelevantState.makerBalance).to.be.bignumber.equal(remainingMakerBalance);
+                    if (eventCount === 2) {
+                        done();
+                    }
+                });
+                zeroEx.orderStateWatcher.subscribe(callback);
+                const shouldThrowOnInsufficientBalanceOrAllowance = true;
+                await zeroEx.exchange.fillOrderAsync(
+                    signedOrder, fillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance, taker,
+                );
+            })().catch(done);
+        });
+        describe('remainingFillableMakerTokenAmount', () => {
+          it('should calculate correct remaining fillable', (done: DoneCallback) => {
+              (async () => {
+                  const takerFillableAmount = new BigNumber(10);
+                  const makerFillableAmount = new BigNumber(20);
+                  signedOrder = await fillScenarios.createAsymmetricFillableSignedOrderAsync(
+                      makerToken.address, takerToken.address, maker, taker, makerFillableAmount, takerFillableAmount);
+                  const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
+                  const takerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, taker);
+                  const fillAmountInBaseUnits = new BigNumber(2);
+                  const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                  zeroEx.orderStateWatcher.addOrder(signedOrder);
+                  let eventCount = 0;
+                  const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                      eventCount++;
+                      expect(orderState.isValid).to.be.true();
+                      const validOrderState = orderState as OrderStateValid;
+                      expect(validOrderState.orderHash).to.be.equal(orderHash);
+                      const orderRelevantState = validOrderState.orderRelevantState;
+                      expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
+                          new BigNumber(16));
+                      if (eventCount === 2) {
+                          done();
+                      }
+                  });
+                  zeroEx.orderStateWatcher.subscribe(callback);
+                  const shouldThrowOnInsufficientBalanceOrAllowance = true;
+                  await zeroEx.exchange.fillOrderAsync(
+                      signedOrder, fillAmountInBaseUnits, shouldThrowOnInsufficientBalanceOrAllowance, taker,
+                  );
+              })().catch(done);
+          });
+          it('should equal approved amount when approved amount is lowest', (done: DoneCallback) => {
+              (async () => {
+                  signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                      makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                  );
+
+                  const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
+
+                  const changedMakerApprovalAmount = new BigNumber(3);
+                  zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                  const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                      const validOrderState = orderState as OrderStateValid;
+                      const orderRelevantState = validOrderState.orderRelevantState;
+                      expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
+                          changedMakerApprovalAmount);
+                      done();
+                  });
+                  zeroEx.orderStateWatcher.subscribe(callback);
+                  await zeroEx.token.setProxyAllowanceAsync(makerToken.address, maker, changedMakerApprovalAmount);
+              })().catch(done);
+          });
+          it('should equal balance amount when balance amount is lowest', (done: DoneCallback) => {
+              (async () => {
+                  signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                      makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                  );
+
+                  const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
+
+                  const remainingAmount = new BigNumber(1);
+                  const transferAmount = makerBalance.sub(remainingAmount);
+                  zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                  const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                      const validOrderState = orderState as OrderStateValid;
+                      const orderRelevantState = validOrderState.orderRelevantState;
+                      expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
+                          remainingAmount);
+                      done();
+                  });
+                  zeroEx.orderStateWatcher.subscribe(callback);
+                  await zeroEx.token.transferAsync(
+                      makerToken.address, maker, ZeroEx.NULL_ADDRESS, transferAmount);
+              })().catch(done);
+          });
+        });
+        it('should emit orderStateInvalid when watched order cancelled', (done: DoneCallback) => {
+            (async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                );
+                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    expect(orderState.isValid).to.be.false();
+                    const invalidOrderState = orderState as OrderStateInvalid;
+                    expect(invalidOrderState.orderHash).to.be.equal(orderHash);
+                    expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.OrderRemainingFillAmountZero);
+                    done();
+                });
+                zeroEx.orderStateWatcher.subscribe(callback);
+
+                const shouldThrowOnInsufficientBalanceOrAllowance = true;
+                await zeroEx.exchange.cancelOrderAsync(signedOrder, fillableAmount);
+            })().catch(done);
+        });
+        it('should emit orderStateValid when watched order partially cancelled', (done: DoneCallback) => {
+            (async () => {
+                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
+                );
+
+                const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
+                const takerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, taker);
+
+                const cancelAmountInBaseUnits = new BigNumber(2);
+                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                    expect(orderState.isValid).to.be.true();
+                    const validOrderState = orderState as OrderStateValid;
+                    expect(validOrderState.orderHash).to.be.equal(orderHash);
+                    const orderRelevantState = validOrderState.orderRelevantState;
+                    expect(orderRelevantState.canceledTakerTokenAmount).to.be.bignumber.equal(cancelAmountInBaseUnits);
+                    done();
+                });
+                zeroEx.orderStateWatcher.subscribe(callback);
+                await zeroEx.exchange.cancelOrderAsync(signedOrder, cancelAmountInBaseUnits);
+            })().catch(done);
+        });
+    });
+});
diff --git a/packages/0x.js/test/order_validation_test.ts b/packages/0x.js/test/order_validation_test.ts
new file mode 100644
index 000000000..4f18742d3
--- /dev/null
+++ b/packages/0x.js/test/order_validation_test.ts
@@ -0,0 +1,327 @@
+import * as chai from 'chai';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import * as Sinon from 'sinon';
+import {chaiSetup} from './utils/chai_setup';
+import {web3Factory} from './utils/web3_factory';
+import {ZeroEx, SignedOrder, Token, ExchangeContractErrs, ZeroExError} from '../src';
+import {TradeSide, TransferType} from '../src/types';
+import {TokenUtils} from './utils/token_utils';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {FillScenarios} from './utils/fill_scenarios';
+import {OrderValidationUtils} from '../src/utils/order_validation_utils';
+import {ExchangeTransferSimulator} from '../src/utils/exchange_transfer_simulator';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+describe('OrderValidation', () => {
+    let web3: Web3;
+    let zeroEx: ZeroEx;
+    let userAddresses: string[];
+    let tokens: Token[];
+    let tokenUtils: TokenUtils;
+    let exchangeContractAddress: string;
+    let zrxTokenAddress: string;
+    let fillScenarios: FillScenarios;
+    let makerTokenAddress: string;
+    let takerTokenAddress: string;
+    let coinbase: string;
+    let makerAddress: string;
+    let takerAddress: string;
+    let feeRecipient: string;
+    let orderValidationUtils: OrderValidationUtils;
+    const fillableAmount = new BigNumber(5);
+    const fillTakerAmount = new BigNumber(5);
+    before(async () => {
+        web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider);
+        exchangeContractAddress = await zeroEx.exchange.getContractAddressAsync();
+        userAddresses = await zeroEx.getAvailableAddressesAsync();
+        [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
+        tokenUtils = new TokenUtils(tokens);
+        zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
+        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress, exchangeContractAddress);
+        const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+        makerTokenAddress = makerToken.address;
+        takerTokenAddress = takerToken.address;
+        orderValidationUtils = new OrderValidationUtils(zeroEx.token, zeroEx.exchange);
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('validateOrderFillableOrThrowAsync', () => {
+        it('should succeed if the order is fillable', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            await zeroEx.exchange.validateOrderFillableOrThrowAsync(
+                signedOrder,
+            );
+        });
+        it('should succeed if the order is asymmetric and fillable', async () => {
+            const makerFillableAmount = fillableAmount;
+            const takerFillableAmount = fillableAmount.minus(4);
+            const signedOrder = await fillScenarios.createAsymmetricFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+                makerFillableAmount, takerFillableAmount,
+            );
+            await zeroEx.exchange.validateOrderFillableOrThrowAsync(
+                signedOrder,
+            );
+        });
+        it('should throw when the order is fully filled or cancelled', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            await zeroEx.exchange.cancelOrderAsync(signedOrder, fillableAmount);
+            return expect(zeroEx.exchange.validateOrderFillableOrThrowAsync(
+                signedOrder,
+            )).to.be.rejectedWith(ExchangeContractErrs.OrderRemainingFillAmountZero);
+        });
+        it('should throw when order is expired', async () => {
+            const expirationInPast = new BigNumber(1496826058); // 7th Jun 2017
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+                fillableAmount, expirationInPast,
+            );
+            return expect(zeroEx.exchange.validateOrderFillableOrThrowAsync(
+                signedOrder,
+            )).to.be.rejectedWith(ExchangeContractErrs.OrderFillExpired);
+        });
+    });
+    describe('validateFillOrderAndThrowIfInvalidAsync', () => {
+        it('should throw when the fill amount is zero', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            const zeroFillAmount = new BigNumber(0);
+            return expect(zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(
+                signedOrder, zeroFillAmount, takerAddress,
+            )).to.be.rejectedWith(ExchangeContractErrs.OrderFillAmountZero);
+        });
+        it('should throw when the signature is invalid', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            // 27 <--> 28
+            signedOrder.ecSignature.v = 27 + (28 - signedOrder.ecSignature.v);
+            return expect(zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(
+                signedOrder, fillableAmount, takerAddress,
+            )).to.be.rejectedWith(ZeroExError.InvalidSignature);
+        });
+        it('should throw when the order is fully filled or cancelled', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            await zeroEx.exchange.cancelOrderAsync(signedOrder, fillableAmount);
+            return expect(zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(
+                signedOrder, fillableAmount, takerAddress,
+            )).to.be.rejectedWith(ExchangeContractErrs.OrderRemainingFillAmountZero);
+        });
+        it('should throw when sender is not a taker', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            const nonTakerAddress = userAddresses[6];
+            return expect(zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(
+                signedOrder, fillTakerAmount, nonTakerAddress,
+            )).to.be.rejectedWith(ExchangeContractErrs.TransactionSenderIsNotFillOrderTaker);
+        });
+        it('should throw when order is expired', async () => {
+            const expirationInPast = new BigNumber(1496826058); // 7th Jun 2017
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+                fillableAmount, expirationInPast,
+            );
+            return expect(zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(
+                signedOrder, fillTakerAmount, takerAddress,
+            )).to.be.rejectedWith(ExchangeContractErrs.OrderFillExpired);
+        });
+        it('should throw when there a rounding error would have occurred', async () => {
+            const makerAmount = new BigNumber(3);
+            const takerAmount = new BigNumber(5);
+            const signedOrder = await fillScenarios.createAsymmetricFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+                makerAmount, takerAmount,
+            );
+            const fillTakerAmountThatCausesRoundingError = new BigNumber(3);
+            return expect(zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(
+                signedOrder, fillTakerAmountThatCausesRoundingError, takerAddress,
+            )).to.be.rejectedWith(ExchangeContractErrs.OrderFillRoundingError);
+        });
+    });
+    describe('#validateFillOrKillOrderAndThrowIfInvalidAsync', () => {
+        it('should throw if remaining fillAmount is less then the desired fillAmount', async () => {
+            const signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            const tooLargeFillAmount = new BigNumber(7);
+            const fillAmountDifference = tooLargeFillAmount.minus(fillableAmount);
+            await zeroEx.token.transferAsync(takerTokenAddress, coinbase, takerAddress, fillAmountDifference);
+            await zeroEx.token.setProxyAllowanceAsync(takerTokenAddress, takerAddress, tooLargeFillAmount);
+            await zeroEx.token.transferAsync(makerTokenAddress, coinbase, makerAddress, fillAmountDifference);
+            await zeroEx.token.setProxyAllowanceAsync(makerTokenAddress, makerAddress, tooLargeFillAmount);
+
+            return expect(zeroEx.exchange.validateFillOrKillOrderThrowIfInvalidAsync(
+                signedOrder, tooLargeFillAmount, takerAddress,
+            )).to.be.rejectedWith(ExchangeContractErrs.InsufficientRemainingFillAmount);
+        });
+    });
+    describe('validateCancelOrderAndThrowIfInvalidAsync', () => {
+        let signedOrder: SignedOrder;
+        let orderHashHex: string;
+        const cancelAmount = new BigNumber(3);
+        beforeEach(async () => {
+            [coinbase, makerAddress, takerAddress] = userAddresses;
+            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            makerTokenAddress = makerToken.address;
+            takerTokenAddress = takerToken.address;
+            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
+            );
+            orderHashHex = ZeroEx.getOrderHashHex(signedOrder);
+        });
+        it('should throw when cancel amount is zero', async () => {
+            const zeroCancelAmount = new BigNumber(0);
+            return expect(zeroEx.exchange.validateCancelOrderThrowIfInvalidAsync(signedOrder, zeroCancelAmount))
+                .to.be.rejectedWith(ExchangeContractErrs.OrderCancelAmountZero);
+        });
+        it('should throw when order is expired', async () => {
+            const expirationInPast = new BigNumber(1496826058); // 7th Jun 2017
+            const expiredSignedOrder = await fillScenarios.createFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+                fillableAmount, expirationInPast,
+            );
+            orderHashHex = ZeroEx.getOrderHashHex(expiredSignedOrder);
+            return expect(zeroEx.exchange.validateCancelOrderThrowIfInvalidAsync(expiredSignedOrder, cancelAmount))
+                .to.be.rejectedWith(ExchangeContractErrs.OrderCancelExpired);
+        });
+        it('should throw when order is already cancelled or filled', async () => {
+            await zeroEx.exchange.cancelOrderAsync(signedOrder, fillableAmount);
+            return expect(zeroEx.exchange.validateCancelOrderThrowIfInvalidAsync(signedOrder, fillableAmount))
+                .to.be.rejectedWith(ExchangeContractErrs.OrderAlreadyCancelledOrFilled);
+        });
+    });
+    describe('#validateFillOrderBalancesAllowancesThrowIfInvalidAsync', () => {
+        let exchangeTransferSimulator: ExchangeTransferSimulator;
+        let transferFromAsync: Sinon.SinonSpy;
+        const bigNumberMatch = (expected: BigNumber) => {
+            return Sinon.match((value: BigNumber) => value.eq(expected));
+        };
+        beforeEach('create exchangeTransferSimulator', async () => {
+            exchangeTransferSimulator = new ExchangeTransferSimulator(zeroEx.token);
+            transferFromAsync = Sinon.spy();
+            exchangeTransferSimulator.transferFromAsync = transferFromAsync as any;
+        });
+        it('should call exchangeTransferSimulator.transferFrom in a correct order', async () => {
+            const makerFee = new BigNumber(2);
+            const takerFee = new BigNumber(2);
+            const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                makerTokenAddress, takerTokenAddress, makerFee, takerFee,
+                makerAddress, takerAddress, fillableAmount, feeRecipient,
+            );
+            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+                exchangeTransferSimulator, signedOrder, fillableAmount, takerAddress, zrxTokenAddress,
+            );
+            expect(transferFromAsync.callCount).to.be.equal(4);
+            expect(
+                transferFromAsync.getCall(0).calledWith(
+                    makerTokenAddress, makerAddress, takerAddress, bigNumberMatch(fillableAmount),
+                    TradeSide.Maker, TransferType.Trade,
+                ),
+            ).to.be.true();
+            expect(
+                transferFromAsync.getCall(1).calledWith(
+                    takerTokenAddress, takerAddress, makerAddress, bigNumberMatch(fillableAmount),
+                    TradeSide.Taker, TransferType.Trade,
+                ),
+            ).to.be.true();
+            expect(
+                transferFromAsync.getCall(2).calledWith(
+                    zrxTokenAddress, makerAddress, feeRecipient, bigNumberMatch(makerFee),
+                    TradeSide.Maker, TransferType.Fee,
+                ),
+            ).to.be.true();
+            expect(
+                transferFromAsync.getCall(3).calledWith(
+                    zrxTokenAddress, takerAddress, feeRecipient, bigNumberMatch(takerFee),
+                    TradeSide.Taker, TransferType.Fee,
+                ),
+            ).to.be.true();
+        });
+        it('should call exchangeTransferSimulator.transferFrom with correct values for an open order', async () => {
+            const makerFee = new BigNumber(2);
+            const takerFee = new BigNumber(2);
+            const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                makerTokenAddress, takerTokenAddress, makerFee, takerFee,
+                makerAddress, ZeroEx.NULL_ADDRESS, fillableAmount, feeRecipient,
+            );
+            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+                exchangeTransferSimulator, signedOrder, fillableAmount, takerAddress, zrxTokenAddress,
+            );
+            expect(transferFromAsync.callCount).to.be.equal(4);
+            expect(
+                transferFromAsync.getCall(0).calledWith(
+                    makerTokenAddress, makerAddress, takerAddress, bigNumberMatch(fillableAmount),
+                    TradeSide.Maker, TransferType.Trade,
+                ),
+            ).to.be.true();
+            expect(
+                transferFromAsync.getCall(1).calledWith(
+                    takerTokenAddress, takerAddress, makerAddress, bigNumberMatch(fillableAmount),
+                    TradeSide.Taker, TransferType.Trade,
+                ),
+            ).to.be.true();
+            expect(
+                transferFromAsync.getCall(2).calledWith(
+                    zrxTokenAddress, makerAddress, feeRecipient, bigNumberMatch(makerFee),
+                    TradeSide.Maker, TransferType.Fee,
+                ),
+            ).to.be.true();
+            expect(
+                transferFromAsync.getCall(3).calledWith(
+                    zrxTokenAddress, takerAddress, feeRecipient, bigNumberMatch(takerFee),
+                    TradeSide.Taker, TransferType.Fee,
+                ),
+            ).to.be.true();
+        });
+        it('should correctly round the fillMakerTokenAmount', async () => {
+            const makerTokenAmount = new BigNumber(3);
+            const takerTokenAmount = new BigNumber(1);
+            const signedOrder = await fillScenarios.createAsymmetricFillableSignedOrderAsync(
+                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, makerTokenAmount, takerTokenAmount,
+            );
+            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+                exchangeTransferSimulator, signedOrder, takerTokenAmount, takerAddress, zrxTokenAddress,
+            );
+            expect(transferFromAsync.callCount).to.be.equal(4);
+            const makerFillAmount = transferFromAsync.getCall(0).args[3];
+            expect(makerFillAmount).to.be.bignumber.equal(makerTokenAmount);
+        });
+        it('should correctly round the makerFeeAmount', async () => {
+            const makerFee = new BigNumber(2);
+            const takerFee = new BigNumber(4);
+            const signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                makerTokenAddress, takerTokenAddress, makerFee, takerFee, makerAddress, takerAddress,
+                fillableAmount, ZeroEx.NULL_ADDRESS,
+            );
+            const fillTakerTokenAmount = fillableAmount.div(2).round(0);
+            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+                exchangeTransferSimulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress,
+            );
+            const makerPartialFee = makerFee.div(2);
+            const takerPartialFee = takerFee.div(2);
+            expect(transferFromAsync.callCount).to.be.equal(4);
+            const partialMakerFee = transferFromAsync.getCall(2).args[3];
+            expect(partialMakerFee).to.be.bignumber.equal(makerPartialFee);
+            const partialTakerFee = transferFromAsync.getCall(3).args[3];
+            expect(partialTakerFee).to.be.bignumber.equal(takerPartialFee);
+        });
+    });
+});
diff --git a/packages/0x.js/test/subscription_test.ts b/packages/0x.js/test/subscription_test.ts
new file mode 100644
index 000000000..985fdc1d6
--- /dev/null
+++ b/packages/0x.js/test/subscription_test.ts
@@ -0,0 +1,95 @@
+import 'mocha';
+import * as _ from 'lodash';
+import * as chai from 'chai';
+import * as Sinon from 'sinon';
+import {chaiSetup} from './utils/chai_setup';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import promisify = require('es6-promisify');
+import {web3Factory} from './utils/web3_factory';
+import {
+    ZeroEx,
+    ZeroExError,
+    Token,
+    ApprovalContractEventArgs,
+    TokenEvents,
+    LogEvent,
+} from '../src';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {TokenUtils} from './utils/token_utils';
+import {DoneCallback, BlockParamLiteral} from '../src/types';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+describe('SubscriptionTest', () => {
+    let web3: Web3;
+    let zeroEx: ZeroEx;
+    let userAddresses: string[];
+    let tokens: Token[];
+    let tokenUtils: TokenUtils;
+    let coinbase: string;
+    let addressWithoutFunds: string;
+    before(async () => {
+        web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider);
+        userAddresses = await zeroEx.getAvailableAddressesAsync();
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
+        tokenUtils = new TokenUtils(tokens);
+        coinbase = userAddresses[0];
+        addressWithoutFunds = userAddresses[1];
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('#subscribe', () => {
+        const indexFilterValues = {};
+        const shouldThrowOnInsufficientBalanceOrAllowance = true;
+        let tokenAddress: string;
+        const transferAmount = new BigNumber(42);
+        const allowanceAmount = new BigNumber(42);
+        let stubs: Sinon.SinonStub[] = [];
+        before(() => {
+            const token = tokens[0];
+            tokenAddress = token.address;
+        });
+        afterEach(() => {
+            zeroEx.token.unsubscribeAll();
+            _.each(stubs, s => s.restore());
+            stubs = [];
+        });
+        it('Should receive the Error when an error occurs', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: LogEvent<ApprovalContractEventArgs>) => {
+                    expect(err).to.not.be.null();
+                    expect(logEvent).to.be.undefined();
+                    done();
+                };
+                stubs = [
+                  Sinon.stub((zeroEx as any)._web3Wrapper, 'getBlockAsync')
+                   .throws("JSON RPC error")
+                ]
+                zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
+                await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
+            })().catch(done);
+         });
+        it('Should allow unsubscribeAll to be called successfully after an error', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: LogEvent<ApprovalContractEventArgs>) => { };
+                zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
+                stubs = [
+                  Sinon.stub((zeroEx as any)._web3Wrapper, 'getBlockAsync')
+                   .throws("JSON RPC error")
+                ]
+                zeroEx.token.unsubscribeAll();
+                done();
+            })().catch(done);
+         });
+    })
+  })
\ No newline at end of file
diff --git a/packages/0x.js/test/token_registry_wrapper_test.ts b/packages/0x.js/test/token_registry_wrapper_test.ts
new file mode 100644
index 000000000..6b5dd517e
--- /dev/null
+++ b/packages/0x.js/test/token_registry_wrapper_test.ts
@@ -0,0 +1,123 @@
+import * as _ from 'lodash';
+import 'mocha';
+import * as chai from 'chai';
+import {SchemaValidator, schemas} from '0x-json-schemas';
+import {chaiSetup} from './utils/chai_setup';
+import {web3Factory} from './utils/web3_factory';
+import {ZeroEx, Token} from '../src';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+const TOKEN_REGISTRY_SIZE_AFTER_MIGRATION = 7;
+
+describe('TokenRegistryWrapper', () => {
+    let zeroEx: ZeroEx;
+    let tokens: Token[];
+    const tokenAddressBySymbol: {[symbol: string]: string} = {};
+    const tokenAddressByName: {[symbol: string]: string} = {};
+    const tokenBySymbol: {[symbol: string]: Token} = {};
+    const tokenByName: {[symbol: string]: Token} = {};
+    const registeredSymbol = 'ZRX';
+    const registeredName = '0x Protocol Token';
+    const unregisteredSymbol = 'MAL';
+    const unregisteredName = 'Malicious Token';
+    before(async () => {
+        const web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider);
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
+        _.map(tokens, token => {
+            tokenAddressBySymbol[token.symbol] = token.address;
+            tokenAddressByName[token.name] = token.address;
+            tokenBySymbol[token.symbol] = token;
+            tokenByName[token.name] = token;
+        });
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('#getTokensAsync', () => {
+        it('should return all the tokens added to the tokenRegistry during the migration', async () => {
+            expect(tokens).to.have.lengthOf(TOKEN_REGISTRY_SIZE_AFTER_MIGRATION);
+
+            const schemaValidator = new SchemaValidator();
+            _.each(tokens, token => {
+                const validationResult = schemaValidator.validate(token, schemas.tokenSchema);
+                expect(validationResult.errors).to.have.lengthOf(0);
+            });
+        });
+    });
+    describe('#getTokenAddressesAsync', () => {
+        it('should return all the token addresses added to the tokenRegistry during the migration', async () => {
+            const tokenAddresses = await zeroEx.tokenRegistry.getTokenAddressesAsync();
+            expect(tokenAddresses).to.have.lengthOf(TOKEN_REGISTRY_SIZE_AFTER_MIGRATION);
+
+            const schemaValidator = new SchemaValidator();
+            _.each(tokenAddresses, tokenAddress => {
+                const validationResult = schemaValidator.validate(tokenAddress, schemas.addressSchema);
+                expect(validationResult.errors).to.have.lengthOf(0);
+                expect(tokenAddress).to.not.be.equal(ZeroEx.NULL_ADDRESS);
+            });
+        });
+    });
+    describe('#getTokenAddressBySymbol', () => {
+        it('should return correct address for a token in the registry', async () => {
+            const tokenAddress = await zeroEx.tokenRegistry.getTokenAddressBySymbolIfExistsAsync(registeredSymbol);
+            expect(tokenAddress).to.be.equal(tokenAddressBySymbol[registeredSymbol]);
+        });
+        it('should return undefined for a token out of registry', async () => {
+            const tokenAddress = await zeroEx.tokenRegistry.getTokenAddressBySymbolIfExistsAsync(unregisteredSymbol);
+            expect(tokenAddress).to.be.undefined();
+        });
+    });
+    describe('#getTokenAddressByName', () => {
+        it('should return correct address for a token in the registry', async () => {
+            const tokenAddress = await zeroEx.tokenRegistry.getTokenAddressByNameIfExistsAsync(registeredName);
+            expect(tokenAddress).to.be.equal(tokenAddressByName[registeredName]);
+        });
+        it('should return undefined for a token out of registry', async () => {
+            const tokenAddress = await zeroEx.tokenRegistry.getTokenAddressByNameIfExistsAsync(unregisteredName);
+            expect(tokenAddress).to.be.undefined();
+        });
+    });
+    describe('#getTokenBySymbol', () => {
+        it('should return correct token for a token in the registry', async () => {
+            const token = await zeroEx.tokenRegistry.getTokenBySymbolIfExistsAsync(registeredSymbol);
+            expect(token).to.be.deep.equal(tokenBySymbol[registeredSymbol]);
+        });
+        it('should return undefined for a token out of registry', async () => {
+            const token = await zeroEx.tokenRegistry.getTokenBySymbolIfExistsAsync(unregisteredSymbol);
+            expect(token).to.be.undefined();
+        });
+    });
+    describe('#getTokenByName', () => {
+        it('should return correct token for a token in the registry', async () => {
+            const token = await zeroEx.tokenRegistry.getTokenByNameIfExistsAsync(registeredName);
+            expect(token).to.be.deep.equal(tokenByName[registeredName]);
+        });
+        it('should return undefined for a token out of registry', async () => {
+            const token = await zeroEx.tokenRegistry.getTokenByNameIfExistsAsync(unregisteredName);
+            expect(token).to.be.undefined();
+        });
+    });
+    describe('#getTokenIfExistsAsync', () => {
+        it('should return the token added to the tokenRegistry during the migration', async () => {
+            const aToken = tokens[0];
+
+            const token = await zeroEx.tokenRegistry.getTokenIfExistsAsync(aToken.address);
+            const schemaValidator = new SchemaValidator();
+            const validationResult = schemaValidator.validate(token, schemas.tokenSchema);
+            expect(validationResult.errors).to.have.lengthOf(0);
+        });
+        it('should return return undefined when passed a token address not in the tokenRegistry', async () => {
+            const unregisteredTokenAddress = '0x5409ed021d9299bf6814279a6a1411a7e866a631';
+            const tokenIfExists = await zeroEx.tokenRegistry.getTokenIfExistsAsync(unregisteredTokenAddress);
+            expect(tokenIfExists).to.be.undefined();
+        });
+    });
+});
diff --git a/packages/0x.js/test/token_transfer_proxy_wrapper_test.ts b/packages/0x.js/test/token_transfer_proxy_wrapper_test.ts
new file mode 100644
index 000000000..8faef0b30
--- /dev/null
+++ b/packages/0x.js/test/token_transfer_proxy_wrapper_test.ts
@@ -0,0 +1,31 @@
+import * as chai from 'chai';
+import {chaiSetup} from './utils/chai_setup';
+import {web3Factory} from './utils/web3_factory';
+import {ZeroEx} from '../src';
+import {TokenTransferProxyWrapper} from '../src/contract_wrappers/token_transfer_proxy_wrapper';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+describe('TokenTransferProxyWrapper', () => {
+    let zeroEx: ZeroEx;
+    before(async () => {
+        const web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider);
+    });
+    describe('#isAuthorizedAsync', () => {
+        it('should return false if the address is not authorized', async () => {
+            const isAuthorized = await zeroEx.proxy.isAuthorizedAsync(ZeroEx.NULL_ADDRESS);
+            expect(isAuthorized).to.be.false();
+        });
+    });
+    describe('#getAuthorizedAddressesAsync', () => {
+        it('should return the list of authorized addresses', async () => {
+            const authorizedAddresses = await zeroEx.proxy.getAuthorizedAddressesAsync();
+            for (const authorizedAddress of authorizedAddresses) {
+                const isAuthorized = await zeroEx.proxy.isAuthorizedAsync(authorizedAddress);
+                expect(isAuthorized).to.be.true();
+            }
+        });
+    });
+});
diff --git a/packages/0x.js/test/token_wrapper_test.ts b/packages/0x.js/test/token_wrapper_test.ts
new file mode 100644
index 000000000..b30762e8c
--- /dev/null
+++ b/packages/0x.js/test/token_wrapper_test.ts
@@ -0,0 +1,477 @@
+import 'mocha';
+import * as chai from 'chai';
+import {chaiSetup} from './utils/chai_setup';
+import * as Web3 from 'web3';
+import BigNumber from 'bignumber.js';
+import promisify = require('es6-promisify');
+import {web3Factory} from './utils/web3_factory';
+import {
+    ZeroEx,
+    ZeroExError,
+    Token,
+    SubscriptionOpts,
+    TokenEvents,
+    ContractEvent,
+    TransferContractEventArgs,
+    ApprovalContractEventArgs,
+    TokenContractEventArgs,
+    LogWithDecodedArgs,
+    LogEvent,
+    DecodedLogEvent,
+} from '../src';
+import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {TokenUtils} from './utils/token_utils';
+import {DoneCallback, BlockParamLiteral} from '../src/types';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle();
+
+describe('TokenWrapper', () => {
+    let web3: Web3;
+    let zeroEx: ZeroEx;
+    let userAddresses: string[];
+    let tokens: Token[];
+    let tokenUtils: TokenUtils;
+    let coinbase: string;
+    let addressWithoutFunds: string;
+    before(async () => {
+        web3 = web3Factory.create();
+        zeroEx = new ZeroEx(web3.currentProvider);
+        userAddresses = await zeroEx.getAvailableAddressesAsync();
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
+        tokenUtils = new TokenUtils(tokens);
+        coinbase = userAddresses[0];
+        addressWithoutFunds = userAddresses[1];
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('#transferAsync', () => {
+        let token: Token;
+        let transferAmount: BigNumber;
+        before(() => {
+            token = tokens[0];
+            transferAmount = new BigNumber(42);
+        });
+        it('should successfully transfer tokens', async () => {
+            const fromAddress = coinbase;
+            const toAddress = addressWithoutFunds;
+            const preBalance = await zeroEx.token.getBalanceAsync(token.address, toAddress);
+            expect(preBalance).to.be.bignumber.equal(0);
+            const txHash = await zeroEx.token.transferAsync(token.address, fromAddress, toAddress, transferAmount);
+            const receipt = await zeroEx.awaitTransactionMinedAsync(txHash);
+            const postBalance = await zeroEx.token.getBalanceAsync(token.address, toAddress);
+            return expect(postBalance).to.be.bignumber.equal(transferAmount);
+        });
+        it('should fail to transfer tokens if fromAddress has an insufficient balance', async () => {
+            const fromAddress = addressWithoutFunds;
+            const toAddress = coinbase;
+            return expect(zeroEx.token.transferAsync(
+                token.address, fromAddress, toAddress, transferAmount,
+            )).to.be.rejectedWith(ZeroExError.InsufficientBalanceForTransfer);
+        });
+        it('should throw a CONTRACT_DOES_NOT_EXIST error for a non-existent token contract', async () => {
+            const nonExistentTokenAddress = '0x9dd402f14d67e001d8efbe6583e51bf9706aa065';
+            const fromAddress = coinbase;
+            const toAddress = coinbase;
+            return expect(zeroEx.token.transferAsync(
+                nonExistentTokenAddress, fromAddress, toAddress, transferAmount,
+            )).to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+        });
+    });
+    describe('#transferFromAsync', () => {
+        let token: Token;
+        let toAddress: string;
+        let senderAddress: string;
+        before(async () => {
+            token = tokens[0];
+            toAddress = addressWithoutFunds;
+            senderAddress = userAddresses[2];
+        });
+        it('should fail to transfer tokens if fromAddress has insufficient allowance set', async () => {
+            const fromAddress = coinbase;
+            const transferAmount = new BigNumber(42);
+
+            const fromAddressBalance = await zeroEx.token.getBalanceAsync(token.address, fromAddress);
+            expect(fromAddressBalance).to.be.bignumber.greaterThan(transferAmount);
+
+            const fromAddressAllowance = await zeroEx.token.getAllowanceAsync(token.address, fromAddress,
+                                                                              toAddress);
+            expect(fromAddressAllowance).to.be.bignumber.equal(0);
+
+            return expect(zeroEx.token.transferFromAsync(
+                token.address, fromAddress, toAddress, senderAddress, transferAmount,
+            )).to.be.rejectedWith(ZeroExError.InsufficientAllowanceForTransfer);
+        });
+        it('[regression] should fail to transfer tokens if set allowance for toAddress instead of senderAddress',
+            async () => {
+            const fromAddress = coinbase;
+            const transferAmount = new BigNumber(42);
+
+            await zeroEx.token.setAllowanceAsync(token.address, fromAddress, toAddress, transferAmount);
+
+            return expect(zeroEx.token.transferFromAsync(
+                token.address, fromAddress, toAddress, senderAddress, transferAmount,
+            )).to.be.rejectedWith(ZeroExError.InsufficientAllowanceForTransfer);
+        });
+        it('should fail to transfer tokens if fromAddress has insufficient balance', async () => {
+            const fromAddress = addressWithoutFunds;
+            const transferAmount = new BigNumber(42);
+
+            const fromAddressBalance = await zeroEx.token.getBalanceAsync(token.address, fromAddress);
+            expect(fromAddressBalance).to.be.bignumber.equal(0);
+
+            await zeroEx.token.setAllowanceAsync(token.address, fromAddress, senderAddress, transferAmount);
+            const fromAddressAllowance = await zeroEx.token.getAllowanceAsync(token.address, fromAddress,
+                                                                              senderAddress);
+            expect(fromAddressAllowance).to.be.bignumber.equal(transferAmount);
+
+            return expect(zeroEx.token.transferFromAsync(
+                token.address, fromAddress, toAddress, senderAddress, transferAmount,
+            )).to.be.rejectedWith(ZeroExError.InsufficientBalanceForTransfer);
+        });
+        it('should successfully transfer tokens', async () => {
+            const fromAddress = coinbase;
+
+            const preBalance = await zeroEx.token.getBalanceAsync(token.address, toAddress);
+            expect(preBalance).to.be.bignumber.equal(0);
+
+            const transferAmount = new BigNumber(42);
+            await zeroEx.token.setAllowanceAsync(token.address, fromAddress, senderAddress, transferAmount);
+
+            await zeroEx.token.transferFromAsync(token.address, fromAddress, toAddress, senderAddress,
+                                                 transferAmount);
+            const postBalance = await zeroEx.token.getBalanceAsync(token.address, toAddress);
+            return expect(postBalance).to.be.bignumber.equal(transferAmount);
+        });
+        it('should throw a CONTRACT_DOES_NOT_EXIST error for a non-existent token contract', async () => {
+            const fromAddress = coinbase;
+            const nonExistentTokenAddress = '0x9dd402f14d67e001d8efbe6583e51bf9706aa065';
+            return expect(zeroEx.token.transferFromAsync(
+                nonExistentTokenAddress, fromAddress, toAddress, senderAddress, new BigNumber(42),
+            )).to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+        });
+    });
+    describe('#getBalanceAsync', () => {
+        describe('With web3 provider with accounts', () => {
+            it('should return the balance for an existing ERC20 token', async () => {
+                const token = tokens[0];
+                const ownerAddress = coinbase;
+                const balance = await zeroEx.token.getBalanceAsync(token.address, ownerAddress);
+                const expectedBalance = new BigNumber('1000000000000000000000000000');
+                return expect(balance).to.be.bignumber.equal(expectedBalance);
+            });
+            it('should throw a CONTRACT_DOES_NOT_EXIST error for a non-existent token contract', async () => {
+                const nonExistentTokenAddress = '0x9dd402f14d67e001d8efbe6583e51bf9706aa065';
+                const ownerAddress = coinbase;
+                return expect(zeroEx.token.getBalanceAsync(nonExistentTokenAddress, ownerAddress))
+                    .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+            });
+            it('should return a balance of 0 for a non-existent owner address', async () => {
+                const token = tokens[0];
+                const nonExistentOwner = '0x198c6ad858f213fb31b6fe809e25040e6b964593';
+                const balance = await zeroEx.token.getBalanceAsync(token.address, nonExistentOwner);
+                const expectedBalance = new BigNumber(0);
+                return expect(balance).to.be.bignumber.equal(expectedBalance);
+            });
+        });
+        describe('With web3 provider without accounts', () => {
+            let zeroExWithoutAccounts: ZeroEx;
+            before(async () => {
+                const hasAddresses = false;
+                const web3WithoutAccounts = web3Factory.create(hasAddresses);
+                zeroExWithoutAccounts = new ZeroEx(web3WithoutAccounts.currentProvider);
+            });
+            it('should return balance even when called with Web3 provider instance without addresses', async () => {
+                    const token = tokens[0];
+                    const ownerAddress = coinbase;
+                    const balance = await zeroExWithoutAccounts.token.getBalanceAsync(token.address, ownerAddress);
+                    const expectedBalance = new BigNumber('1000000000000000000000000000');
+                    return expect(balance).to.be.bignumber.equal(expectedBalance);
+            });
+        });
+    });
+    describe('#setAllowanceAsync', () => {
+        it('should set the spender\'s allowance', async () => {
+            const token = tokens[0];
+            const ownerAddress = coinbase;
+            const spenderAddress = addressWithoutFunds;
+
+            const allowanceBeforeSet = await zeroEx.token.getAllowanceAsync(token.address, ownerAddress,
+                                                                            spenderAddress);
+            const expectedAllowanceBeforeAllowanceSet = new BigNumber(0);
+            expect(allowanceBeforeSet).to.be.bignumber.equal(expectedAllowanceBeforeAllowanceSet);
+
+            const amountInBaseUnits = new BigNumber(50);
+            await zeroEx.token.setAllowanceAsync(token.address, ownerAddress, spenderAddress, amountInBaseUnits);
+
+            const allowanceAfterSet = await zeroEx.token.getAllowanceAsync(token.address, ownerAddress, spenderAddress);
+            const expectedAllowanceAfterAllowanceSet = amountInBaseUnits;
+            return expect(allowanceAfterSet).to.be.bignumber.equal(expectedAllowanceAfterAllowanceSet);
+        });
+    });
+    describe('#setUnlimitedAllowanceAsync', () => {
+        it('should set the unlimited spender\'s allowance', async () => {
+            const token = tokens[0];
+            const ownerAddress = coinbase;
+            const spenderAddress = addressWithoutFunds;
+
+            await zeroEx.token.setUnlimitedAllowanceAsync(token.address, ownerAddress, spenderAddress);
+            const allowance = await zeroEx.token.getAllowanceAsync(token.address, ownerAddress, spenderAddress);
+            return expect(allowance).to.be.bignumber.equal(zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+        });
+        it('should reduce the gas cost for transfers including tokens with unlimited allowance support', async () => {
+            const transferAmount = new BigNumber(5);
+            const zrx = tokenUtils.getProtocolTokenOrThrow();
+            const [, userWithNormalAllowance, userWithUnlimitedAllowance] = userAddresses;
+            await zeroEx.token.setAllowanceAsync(zrx.address, coinbase, userWithNormalAllowance, transferAmount);
+            await zeroEx.token.setUnlimitedAllowanceAsync(zrx.address, coinbase, userWithUnlimitedAllowance);
+
+            const initBalanceWithNormalAllowance = await promisify(web3.eth.getBalance)(userWithNormalAllowance);
+            const initBalanceWithUnlimitedAllowance = await promisify(web3.eth.getBalance)(userWithUnlimitedAllowance);
+
+            await zeroEx.token.transferFromAsync(
+                zrx.address, coinbase, userWithNormalAllowance, userWithNormalAllowance, transferAmount,
+            );
+            await zeroEx.token.transferFromAsync(
+                zrx.address, coinbase, userWithUnlimitedAllowance, userWithUnlimitedAllowance, transferAmount,
+            );
+
+            const finalBalanceWithNormalAllowance = await promisify(web3.eth.getBalance)(userWithNormalAllowance);
+            const finalBalanceWithUnlimitedAllowance = await promisify(web3.eth.getBalance)(userWithUnlimitedAllowance);
+
+            const normalGasCost = initBalanceWithNormalAllowance.minus(finalBalanceWithNormalAllowance);
+            const unlimitedGasCost = initBalanceWithUnlimitedAllowance.minus(finalBalanceWithUnlimitedAllowance);
+
+            // In theory the gas cost with unlimited allowance should be smaller, but with testrpc it's actually bigger.
+            // This needs to be investigated in ethereumjs-vm. This test is essentially a repro.
+            // TODO: Make this test pass with inverted assertion.
+            expect(unlimitedGasCost.toNumber()).to.be.gt(normalGasCost.toNumber());
+        });
+    });
+    describe('#getAllowanceAsync', () => {
+        describe('With web3 provider with accounts', () => {
+            it('should get the proxy allowance', async () => {
+                const token = tokens[0];
+                const ownerAddress = coinbase;
+                const spenderAddress = addressWithoutFunds;
+
+                const amountInBaseUnits = new BigNumber(50);
+                await zeroEx.token.setAllowanceAsync(token.address, ownerAddress, spenderAddress, amountInBaseUnits);
+
+                const allowance = await zeroEx.token.getAllowanceAsync(token.address, ownerAddress, spenderAddress);
+                const expectedAllowance = amountInBaseUnits;
+                return expect(allowance).to.be.bignumber.equal(expectedAllowance);
+            });
+            it('should return 0 if no allowance set yet', async () => {
+                const token = tokens[0];
+                const ownerAddress = coinbase;
+                const spenderAddress = addressWithoutFunds;
+                const allowance = await zeroEx.token.getAllowanceAsync(token.address, ownerAddress, spenderAddress);
+                const expectedAllowance = new BigNumber(0);
+                return expect(allowance).to.be.bignumber.equal(expectedAllowance);
+            });
+        });
+        describe('With web3 provider without accounts', () => {
+            let zeroExWithoutAccounts: ZeroEx;
+            before(async () => {
+                const hasAddresses = false;
+                const web3WithoutAccounts = web3Factory.create(hasAddresses);
+                zeroExWithoutAccounts = new ZeroEx(web3WithoutAccounts.currentProvider);
+            });
+            it('should get the proxy allowance', async () => {
+                const token = tokens[0];
+                const ownerAddress = coinbase;
+                const spenderAddress = addressWithoutFunds;
+
+                const amountInBaseUnits = new BigNumber(50);
+                await zeroEx.token.setAllowanceAsync(token.address, ownerAddress, spenderAddress, amountInBaseUnits);
+
+                const allowance = await zeroExWithoutAccounts.token.getAllowanceAsync(
+                    token.address, ownerAddress, spenderAddress,
+                );
+                const expectedAllowance = amountInBaseUnits;
+                return expect(allowance).to.be.bignumber.equal(expectedAllowance);
+            });
+        });
+    });
+    describe('#getProxyAllowanceAsync', () => {
+        it('should get the proxy allowance', async () => {
+            const token = tokens[0];
+            const ownerAddress = coinbase;
+
+            const amountInBaseUnits = new BigNumber(50);
+            await zeroEx.token.setProxyAllowanceAsync(token.address, ownerAddress, amountInBaseUnits);
+
+            const allowance = await zeroEx.token.getProxyAllowanceAsync(token.address, ownerAddress);
+            const expectedAllowance = amountInBaseUnits;
+            return expect(allowance).to.be.bignumber.equal(expectedAllowance);
+        });
+    });
+    describe('#setProxyAllowanceAsync', () => {
+        it('should set the proxy allowance', async () => {
+            const token = tokens[0];
+            const ownerAddress = coinbase;
+
+            const allowanceBeforeSet = await zeroEx.token.getProxyAllowanceAsync(token.address, ownerAddress);
+            const expectedAllowanceBeforeAllowanceSet = new BigNumber(0);
+            expect(allowanceBeforeSet).to.be.bignumber.equal(expectedAllowanceBeforeAllowanceSet);
+
+            const amountInBaseUnits = new BigNumber(50);
+            await zeroEx.token.setProxyAllowanceAsync(token.address, ownerAddress, amountInBaseUnits);
+
+            const allowanceAfterSet = await zeroEx.token.getProxyAllowanceAsync(token.address, ownerAddress);
+            const expectedAllowanceAfterAllowanceSet = amountInBaseUnits;
+            return expect(allowanceAfterSet).to.be.bignumber.equal(expectedAllowanceAfterAllowanceSet);
+        });
+    });
+    describe('#setUnlimitedProxyAllowanceAsync', () => {
+        it('should set the unlimited proxy allowance', async () => {
+            const token = tokens[0];
+            const ownerAddress = coinbase;
+
+            await zeroEx.token.setUnlimitedProxyAllowanceAsync(token.address, ownerAddress);
+            const allowance = await zeroEx.token.getProxyAllowanceAsync(token.address, ownerAddress);
+            return expect(allowance).to.be.bignumber.equal(zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+        });
+    });
+    describe('#subscribe', () => {
+        const indexFilterValues = {};
+        const shouldThrowOnInsufficientBalanceOrAllowance = true;
+        let tokenAddress: string;
+        const transferAmount = new BigNumber(42);
+        const allowanceAmount = new BigNumber(42);
+        before(() => {
+            const token = tokens[0];
+            tokenAddress = token.address;
+        });
+        afterEach(() => {
+            zeroEx.token.unsubscribeAll();
+        });
+        // Hack: Mocha does not allow a test to be both async and have a `done` callback
+        // Since we need to await the receipt of the event in the `subscribe` callback,
+        // we do need both. A hack is to make the top-level a sync fn w/ a done callback and then
+        // wrap the rest of the test in an async block
+        // Source: https://github.com/mochajs/mocha/issues/2407
+        it('Should receive the Transfer event when tokens are transfered', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: DecodedLogEvent<TransferContractEventArgs>) => {
+                    expect(logEvent).to.not.be.undefined();
+                    const args = logEvent.args;
+                    expect(args._from).to.be.equal(coinbase);
+                    expect(args._to).to.be.equal(addressWithoutFunds);
+                    expect(args._value).to.be.bignumber.equal(transferAmount);
+                    done();
+                };
+                zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Transfer, indexFilterValues, callback);
+                await zeroEx.token.transferAsync(tokenAddress, coinbase, addressWithoutFunds, transferAmount);
+            })().catch(done);
+        });
+        it('Should receive the Approval event when allowance is being set', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    expect(logEvent).to.not.be.undefined();
+                    const args = logEvent.args;
+                    expect(args._owner).to.be.equal(coinbase);
+                    expect(args._spender).to.be.equal(addressWithoutFunds);
+                    expect(args._value).to.be.bignumber.equal(allowanceAmount);
+                    done();
+                };
+                zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
+                await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
+            })().catch(done);
+        });
+        it('Outstanding subscriptions are cancelled when zeroEx.setProviderAsync called', (done: DoneCallback) => {
+            (async () => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    done(new Error('Expected this subscription to have been cancelled'));
+                };
+                zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Transfer, indexFilterValues, callbackNeverToBeCalled,
+                );
+                const callbackToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    done();
+                };
+                const newProvider = web3Factory.getRpcProvider();
+                await zeroEx.setProviderAsync(newProvider);
+                zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Transfer, indexFilterValues, callbackToBeCalled,
+                );
+                await zeroEx.token.transferAsync(tokenAddress, coinbase, addressWithoutFunds, transferAmount);
+            })().catch(done);
+        });
+        it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
+            (async () => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    done(new Error('Expected this subscription to have been cancelled'));
+                };
+                const subscriptionToken = zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Transfer, indexFilterValues, callbackNeverToBeCalled);
+                zeroEx.token.unsubscribe(subscriptionToken);
+                await zeroEx.token.transferAsync(tokenAddress, coinbase, addressWithoutFunds, transferAmount);
+                done();
+            })().catch(done);
+        });
+    });
+    describe('#getLogsAsync', () => {
+        let tokenAddress: string;
+        let tokenTransferProxyAddress: string;
+        const subscriptionOpts: SubscriptionOpts = {
+            fromBlock: BlockParamLiteral.Earliest,
+            toBlock: BlockParamLiteral.Latest,
+        };
+        let txHash: string;
+        before(async () => {
+            const token = tokens[0];
+            tokenAddress = token.address;
+            tokenTransferProxyAddress = await zeroEx.proxy.getContractAddressAsync();
+        });
+        it('should get logs with decoded args emitted by Approval', async () => {
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(tokenAddress, coinbase);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const eventName = TokenEvents.Approval;
+            const indexFilterValues = {};
+            const logs = await zeroEx.token.getLogsAsync<ApprovalContractEventArgs>(
+                tokenAddress, eventName, subscriptionOpts, indexFilterValues,
+            );
+            expect(logs).to.have.length(1);
+            const args = logs[0].args;
+            expect(logs[0].event).to.be.equal(eventName);
+            expect(args._owner).to.be.equal(coinbase);
+            expect(args._spender).to.be.equal(tokenTransferProxyAddress);
+            expect(args._value).to.be.bignumber.equal(zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+        });
+        it('should only get the logs with the correct event name', async () => {
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(tokenAddress, coinbase);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const differentEventName = TokenEvents.Transfer;
+            const indexFilterValues = {};
+            const logs = await zeroEx.token.getLogsAsync(
+                tokenAddress, differentEventName, subscriptionOpts, indexFilterValues,
+            );
+            expect(logs).to.have.length(0);
+        });
+        it('should only get the logs with the correct indexed fields', async () => {
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(tokenAddress, coinbase);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(tokenAddress, addressWithoutFunds);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const eventName = TokenEvents.Approval;
+            const indexFilterValues = {
+                _owner: coinbase,
+            };
+            const logs = await zeroEx.token.getLogsAsync<ApprovalContractEventArgs>(
+                tokenAddress, eventName, subscriptionOpts, indexFilterValues,
+            );
+            expect(logs).to.have.length(1);
+            const args = logs[0].args;
+            expect(args._owner).to.be.equal(coinbase);
+        });
+    });
+});
diff --git a/packages/0x.js/test/utils/blockchain_lifecycle.ts b/packages/0x.js/test/utils/blockchain_lifecycle.ts
new file mode 100644
index 000000000..9a44ccd6f
--- /dev/null
+++ b/packages/0x.js/test/utils/blockchain_lifecycle.ts
@@ -0,0 +1,26 @@
+import {RPC} from './rpc';
+
+export class BlockchainLifecycle {
+    private rpc: RPC;
+    private snapshotIdsStack: number[];
+    constructor() {
+        this.rpc = new RPC();
+        this.snapshotIdsStack = [];
+    }
+    // TODO: In order to run these tests on an actual node, we should check if we are running against
+    // TestRPC, if so, use snapshots, otherwise re-deploy contracts before every test
+    public async startAsync(): Promise<void> {
+        const snapshotId = await this.rpc.takeSnapshotAsync();
+        this.snapshotIdsStack.push(snapshotId);
+    }
+    public async revertAsync(): Promise<void> {
+        const snapshotId = this.snapshotIdsStack.pop() as number;
+        const didRevert = await this.rpc.revertSnapshotAsync(snapshotId);
+        if (!didRevert) {
+            throw new Error(`Snapshot with id #${snapshotId} failed to revert`);
+        }
+    }
+    public async mineABlock(): Promise<void> {
+        await this.rpc.mineBlockAsync();
+    }
+}
diff --git a/packages/0x.js/test/utils/chai_setup.ts b/packages/0x.js/test/utils/chai_setup.ts
new file mode 100644
index 000000000..c18988106
--- /dev/null
+++ b/packages/0x.js/test/utils/chai_setup.ts
@@ -0,0 +1,13 @@
+import * as chai from 'chai';
+import * as dirtyChai from 'dirty-chai';
+import ChaiBigNumber = require('chai-bignumber');
+import chaiAsPromised = require('chai-as-promised');
+
+export const chaiSetup = {
+    configure() {
+        chai.config.includeStack = true;
+        chai.use(ChaiBigNumber());
+        chai.use(dirtyChai);
+        chai.use(chaiAsPromised);
+    },
+};
diff --git a/packages/0x.js/test/utils/constants.ts b/packages/0x.js/test/utils/constants.ts
new file mode 100644
index 000000000..c7d3aebca
--- /dev/null
+++ b/packages/0x.js/test/utils/constants.ts
@@ -0,0 +1,8 @@
+export const constants = {
+    NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
+    RPC_HOST: 'localhost',
+    RPC_PORT: 8545,
+    TESTRPC_NETWORK_ID: 50,
+    KOVAN_RPC_URL: 'https://kovan.infura.io',
+    ROPSTEN_RPC_URL: 'https://ropsten.infura.io',
+};
diff --git a/packages/0x.js/test/utils/fill_scenarios.ts b/packages/0x.js/test/utils/fill_scenarios.ts
new file mode 100644
index 000000000..a0632b12c
--- /dev/null
+++ b/packages/0x.js/test/utils/fill_scenarios.ts
@@ -0,0 +1,114 @@
+import BigNumber from 'bignumber.js';
+import {ZeroEx, Token, SignedOrder} from '../../src';
+import {orderFactory} from '../utils/order_factory';
+import {constants} from './constants';
+
+export class FillScenarios {
+    private zeroEx: ZeroEx;
+    private userAddresses: string[];
+    private tokens: Token[];
+    private coinbase: string;
+    private zrxTokenAddress: string;
+    private exchangeContractAddress: string;
+    constructor(zeroEx: ZeroEx, userAddresses: string[],
+                tokens: Token[], zrxTokenAddress: string, exchangeContractAddress: string) {
+        this.zeroEx = zeroEx;
+        this.userAddresses = userAddresses;
+        this.tokens = tokens;
+        this.coinbase = userAddresses[0];
+        this.zrxTokenAddress = zrxTokenAddress;
+        this.exchangeContractAddress = exchangeContractAddress;
+    }
+    public async createFillableSignedOrderAsync(makerTokenAddress: string, takerTokenAddress: string,
+                                                makerAddress: string, takerAddress: string,
+                                                fillableAmount: BigNumber,
+                                                expirationUnixTimestampSec?: BigNumber):
+                                           Promise<SignedOrder> {
+        return this.createAsymmetricFillableSignedOrderAsync(
+            makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+            fillableAmount, fillableAmount, expirationUnixTimestampSec,
+        );
+    }
+    public async createFillableSignedOrderWithFeesAsync(
+        makerTokenAddress: string, takerTokenAddress: string,
+        makerFee: BigNumber, takerFee: BigNumber,
+        makerAddress: string, takerAddress: string,
+        fillableAmount: BigNumber,
+        feeRecepient: string, expirationUnixTimestampSec?: BigNumber,
+    ): Promise<SignedOrder> {
+        return this.createAsymmetricFillableSignedOrderWithFeesAsync(
+            makerTokenAddress, takerTokenAddress, makerFee, takerFee, makerAddress, takerAddress,
+            fillableAmount, fillableAmount, feeRecepient, expirationUnixTimestampSec,
+        );
+    }
+    public async createAsymmetricFillableSignedOrderAsync(
+        makerTokenAddress: string, takerTokenAddress: string, makerAddress: string, takerAddress: string,
+        makerFillableAmount: BigNumber, takerFillableAmount: BigNumber,
+        expirationUnixTimestampSec?: BigNumber): Promise<SignedOrder> {
+        const makerFee = new BigNumber(0);
+        const takerFee = new BigNumber(0);
+        const feeRecepient = constants.NULL_ADDRESS;
+        return this.createAsymmetricFillableSignedOrderWithFeesAsync(
+            makerTokenAddress, takerTokenAddress, makerFee, takerFee, makerAddress, takerAddress,
+            makerFillableAmount, takerFillableAmount, feeRecepient, expirationUnixTimestampSec,
+        );
+    }
+    public async createPartiallyFilledSignedOrderAsync(makerTokenAddress: string, takerTokenAddress: string,
+                                                       takerAddress: string, fillableAmount: BigNumber,
+                                                       partialFillAmount: BigNumber) {
+        const [makerAddress] = this.userAddresses;
+        const signedOrder = await this.createAsymmetricFillableSignedOrderAsync(
+            makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
+            fillableAmount, fillableAmount,
+        );
+        const shouldThrowOnInsufficientBalanceOrAllowance = false;
+        await this.zeroEx.exchange.fillOrderAsync(
+            signedOrder, partialFillAmount, shouldThrowOnInsufficientBalanceOrAllowance, takerAddress,
+        );
+        return signedOrder;
+    }
+    private async createAsymmetricFillableSignedOrderWithFeesAsync(
+        makerTokenAddress: string, takerTokenAddress: string,
+        makerFee: BigNumber, takerFee: BigNumber,
+        makerAddress: string, takerAddress: string,
+        makerFillableAmount: BigNumber, takerFillableAmount: BigNumber,
+        feeRecepient: string, expirationUnixTimestampSec?: BigNumber): Promise<SignedOrder> {
+
+        await Promise.all([
+            this.increaseBalanceAndAllowanceAsync(makerTokenAddress, makerAddress, makerFillableAmount),
+            this.increaseBalanceAndAllowanceAsync(takerTokenAddress, takerAddress, takerFillableAmount),
+        ]);
+        await Promise.all([
+            this.increaseBalanceAndAllowanceAsync(this.zrxTokenAddress, makerAddress, makerFee),
+            this.increaseBalanceAndAllowanceAsync(this.zrxTokenAddress, takerAddress, takerFee),
+        ]);
+
+        const signedOrder = await orderFactory.createSignedOrderAsync(this.zeroEx,
+            makerAddress, takerAddress, makerFee, takerFee,
+            makerFillableAmount, makerTokenAddress, takerFillableAmount, takerTokenAddress,
+            this.exchangeContractAddress, feeRecepient, expirationUnixTimestampSec);
+        return signedOrder;
+    }
+    private async increaseBalanceAndAllowanceAsync(
+        tokenAddress: string, address: string, amount: BigNumber): Promise<void> {
+        if (amount.isZero() || address === ZeroEx.NULL_ADDRESS) {
+            return; // noop
+        }
+        await Promise.all([
+            this.increaseBalanceAsync(tokenAddress, address, amount),
+            this.increaseAllowanceAsync(tokenAddress, address, amount),
+        ]);
+    }
+    private async increaseBalanceAsync(
+        tokenAddress: string, address: string, amount: BigNumber): Promise<void> {
+        await this.zeroEx.token.transferAsync(tokenAddress, this.coinbase, address, amount);
+    }
+    private async increaseAllowanceAsync(
+        tokenAddress: string, address: string, amount: BigNumber): Promise<void> {
+        const oldMakerAllowance = await this.zeroEx.token.getProxyAllowanceAsync(tokenAddress, address);
+        const newMakerAllowance = oldMakerAllowance.plus(amount);
+        await this.zeroEx.token.setProxyAllowanceAsync(
+            tokenAddress, address, newMakerAllowance,
+        );
+    }
+}
diff --git a/packages/0x.js/test/utils/order_factory.ts b/packages/0x.js/test/utils/order_factory.ts
new file mode 100644
index 000000000..6086e09f7
--- /dev/null
+++ b/packages/0x.js/test/utils/order_factory.ts
@@ -0,0 +1,42 @@
+import * as _ from 'lodash';
+import BigNumber from 'bignumber.js';
+import {ZeroEx, SignedOrder} from '../../src';
+
+export const orderFactory = {
+    async createSignedOrderAsync(
+        zeroEx: ZeroEx,
+        maker: string,
+        taker: string,
+        makerFee: BigNumber,
+        takerFee: BigNumber,
+        makerTokenAmount: BigNumber,
+        makerTokenAddress: string,
+        takerTokenAmount: BigNumber,
+        takerTokenAddress: string,
+        exchangeContractAddress: string,
+        feeRecipient: string,
+        expirationUnixTimestampSec?: BigNumber): Promise<SignedOrder> {
+        const defaultExpirationUnixTimestampSec = new BigNumber(2524604400); // Close to infinite
+        expirationUnixTimestampSec = _.isUndefined(expirationUnixTimestampSec) ?
+            defaultExpirationUnixTimestampSec :
+            expirationUnixTimestampSec;
+        const order = {
+            maker,
+            taker,
+            makerFee,
+            takerFee,
+            makerTokenAmount,
+            takerTokenAmount,
+            makerTokenAddress,
+            takerTokenAddress,
+            salt: ZeroEx.generatePseudoRandomSalt(),
+            exchangeContractAddress,
+            feeRecipient,
+            expirationUnixTimestampSec,
+        };
+        const orderHash = ZeroEx.getOrderHashHex(order);
+        const ecSignature = await zeroEx.signOrderHashAsync(orderHash, maker);
+        const signedOrder: SignedOrder = _.assign(order, {ecSignature});
+        return signedOrder;
+    },
+};
diff --git a/packages/0x.js/test/utils/report_callback_errors.ts b/packages/0x.js/test/utils/report_callback_errors.ts
new file mode 100644
index 000000000..d471b2af2
--- /dev/null
+++ b/packages/0x.js/test/utils/report_callback_errors.ts
@@ -0,0 +1,14 @@
+import { DoneCallback } from '../../src/types';
+
+export const reportCallbackErrors = (done: DoneCallback) => {
+    return (f: (...args: any[]) => void) => {
+        const wrapped = (...args: any[]) => {
+            try {
+                f(...args);
+            } catch (err) {
+                done(err);
+            }
+        };
+        return wrapped;
+    };
+};
diff --git a/packages/0x.js/test/utils/rpc.ts b/packages/0x.js/test/utils/rpc.ts
new file mode 100644
index 000000000..299e72e79
--- /dev/null
+++ b/packages/0x.js/test/utils/rpc.ts
@@ -0,0 +1,57 @@
+import * as ethUtil from 'ethereumjs-util';
+import * as request from 'request-promise-native';
+import {constants} from './constants';
+
+export class RPC {
+    private host: string;
+    private port: number;
+    private id: number;
+    constructor() {
+        this.host = constants.RPC_HOST;
+        this.port = constants.RPC_PORT;
+        this.id = 0;
+    }
+    public async takeSnapshotAsync(): Promise<number> {
+        const method = 'evm_snapshot';
+        const params: any[] = [];
+        const payload = this.toPayload(method, params);
+        const snapshotIdHex = await this.sendAsync(payload);
+        const snapshotId = ethUtil.bufferToInt(ethUtil.toBuffer(snapshotIdHex));
+        return snapshotId;
+    }
+    public async revertSnapshotAsync(snapshotId: number): Promise<boolean> {
+        const method = 'evm_revert';
+        const params = [snapshotId];
+        const payload = this.toPayload(method, params);
+        const didRevert = await this.sendAsync(payload);
+        return didRevert;
+    }
+    public async mineBlockAsync(): Promise<void> {
+        const method = 'evm_mine';
+        const params: any[] = [];
+        const payload = this.toPayload(method, params);
+        await this.sendAsync(payload);
+    }
+    private toPayload(method: string, params: any[] = []): string {
+        const payload = JSON.stringify({
+            id: this.id,
+            method,
+            params,
+        });
+        this.id += 1;
+        return payload;
+    }
+    private async sendAsync(payload: string): Promise<any> {
+        const opts = {
+            method: 'POST',
+            uri: `http://${this.host}:${this.port}`,
+            body: payload,
+            headers: {
+                'content-type': 'application/json',
+            },
+        };
+        const bodyString = await request(opts);
+        const body = JSON.parse(bodyString);
+        return body.result;
+    }
+}
diff --git a/packages/0x.js/test/utils/token_utils.ts b/packages/0x.js/test/utils/token_utils.ts
new file mode 100644
index 000000000..51cb9411c
--- /dev/null
+++ b/packages/0x.js/test/utils/token_utils.ts
@@ -0,0 +1,24 @@
+import * as _ from 'lodash';
+import {Token, InternalZeroExError} from '../../src/types';
+
+const PROTOCOL_TOKEN_SYMBOL = 'ZRX';
+
+export class TokenUtils {
+    private tokens: Token[];
+    constructor(tokens: Token[]) {
+        this.tokens = tokens;
+    }
+    public getProtocolTokenOrThrow(): Token {
+        const zrxToken = _.find(this.tokens, {symbol: PROTOCOL_TOKEN_SYMBOL});
+        if (_.isUndefined(zrxToken)) {
+            throw new Error(InternalZeroExError.ZrxNotInTokenRegistry);
+        }
+        return zrxToken;
+    }
+    public getNonProtocolTokens(): Token[] {
+        const nonProtocolTokens = _.filter(this.tokens, token => {
+            return token.symbol !== PROTOCOL_TOKEN_SYMBOL;
+        });
+        return nonProtocolTokens;
+    }
+}
diff --git a/packages/0x.js/test/utils/web3_factory.ts b/packages/0x.js/test/utils/web3_factory.ts
new file mode 100644
index 000000000..b20070c74
--- /dev/null
+++ b/packages/0x.js/test/utils/web3_factory.ts
@@ -0,0 +1,31 @@
+// HACK: web3 injects XMLHttpRequest into the global scope and ProviderEngine checks XMLHttpRequest
+// to know whether it is running in a browser or node environment. We need it to be undefined since
+// we are not running in a browser env.
+// Filed issue: https://github.com/ethereum/web3.js/issues/844
+(global as any).XMLHttpRequest = undefined;
+import ProviderEngine = require('web3-provider-engine');
+import RpcSubprovider = require('web3-provider-engine/subproviders/rpc');
+import * as Web3 from 'web3';
+import {constants} from './constants';
+import {EmptyWalletSubProvider} from '../../src/subproviders/empty_wallet_subprovider';
+
+export const web3Factory = {
+    create(hasAddresses: boolean = true): Web3 {
+        const provider = this.getRpcProvider(hasAddresses);
+        const web3 = new Web3();
+        web3.setProvider(provider);
+        return web3;
+    },
+    getRpcProvider(hasAddresses: boolean = true): Web3.Provider {
+        const provider = new ProviderEngine();
+        const rpcUrl = `http://${constants.RPC_HOST}:${constants.RPC_PORT}`;
+        if (!hasAddresses) {
+            provider.addProvider(new EmptyWalletSubProvider());
+        }
+        provider.addProvider(new RpcSubprovider({
+            rpcUrl,
+        }));
+        provider.start();
+        return provider;
+    },
+};
diff --git a/packages/0x.js/test/web3_wrapper_test.ts b/packages/0x.js/test/web3_wrapper_test.ts
new file mode 100644
index 000000000..d1c2e8e89
--- /dev/null
+++ b/packages/0x.js/test/web3_wrapper_test.ts
@@ -0,0 +1,29 @@
+import * as chai from 'chai';
+import {web3Factory} from './utils/web3_factory';
+import {ZeroEx} from '../src/';
+import {Web3Wrapper} from '../src/web3_wrapper';
+import {constants} from './utils/constants';
+
+chai.config.includeStack = true;
+const expect = chai.expect;
+
+describe('Web3Wrapper', () => {
+    const web3Provider = web3Factory.create().currentProvider;
+    describe('#getNetworkIdIfExistsAsync', () => {
+        it('caches network id requests', async () => {
+            const web3Wrapper = (new ZeroEx(web3Provider) as any)._web3Wrapper as Web3Wrapper;
+            expect((web3Wrapper as any).networkIdIfExists).to.be.undefined();
+            const networkIdIfExists = await web3Wrapper.getNetworkIdIfExistsAsync();
+            expect((web3Wrapper as any).networkIdIfExists).to.be.equal(constants.TESTRPC_NETWORK_ID);
+        });
+        it('invalidates network id cache on setProvider call', async () => {
+            const web3Wrapper = (new ZeroEx(web3Provider) as any)._web3Wrapper as Web3Wrapper;
+            expect((web3Wrapper as any).networkIdIfExists).to.be.undefined();
+            const networkIdIfExists = await web3Wrapper.getNetworkIdIfExistsAsync();
+            expect((web3Wrapper as any).networkIdIfExists).to.be.equal(constants.TESTRPC_NETWORK_ID);
+            const newProvider = web3Factory.create().currentProvider;
+            web3Wrapper.setProvider(newProvider);
+            expect((web3Wrapper as any).networkIdIfExists).to.be.undefined();
+        });
+    });
+});
diff --git a/packages/0x.js/tsconfig.json b/packages/0x.js/tsconfig.json
new file mode 100644
index 000000000..0684d4f1b
--- /dev/null
+++ b/packages/0x.js/tsconfig.json
@@ -0,0 +1,22 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "target": "es5",
+    "lib": [ "es2015", "dom" ],
+    "outDir": "lib",
+    "sourceMap": true,
+    "declaration": true,
+    "noImplicitAny": true,
+    "experimentalDecorators": true,
+    "strictNullChecks": true
+  },
+  "include": [
+    "./src/**/*",
+    "./test/**/*",
+    "./node_modules/types-bn/index.d.ts",
+    "./node_modules/types-ethereumjs-util/index.d.ts",
+    "./node_modules/web3-typescript-typings/index.d.ts",
+    "./node_modules/chai-typescript-typings/index.d.ts",
+    "./node_modules/chai-as-promised-typescript-typings/index.d.ts"
+  ]
+}
diff --git a/packages/0x.js/webpack.config.js b/packages/0x.js/webpack.config.js
new file mode 100644
index 000000000..61a7e4196
--- /dev/null
+++ b/packages/0x.js/webpack.config.js
@@ -0,0 +1,56 @@
+/**
+ * This is to generate the umd bundle only
+ */
+const _ = require('lodash');
+const webpack = require('webpack');
+const path = require('path');
+const production = process.env.NODE_ENV === 'production';
+
+let entry = {
+    'index': './src/index.ts',
+};
+if (production) {
+    entry = _.assign({}, entry, {'index.min': './src/index.ts'});
+}
+
+module.exports = {
+    entry,
+    output: {
+        path: path.resolve(__dirname, '_bundles'),
+        filename: '[name].js',
+        libraryTarget: 'umd',
+        library: 'ZeroEx',
+        umdNamedDefine: true,
+    },
+    resolve: {
+        extensions: ['.ts', '.js', '.json'],
+    },
+    devtool: 'source-map',
+    plugins: [
+        new webpack.optimize.UglifyJsPlugin({
+            minimize: true,
+            sourceMap: true,
+            include: /\.min\.js$/,
+        }),
+    ],
+    module: {
+        rules: [
+            {
+                test: /\.ts$/,
+                use: [
+                    {
+                        loader: 'awesome-typescript-loader',
+                        query: {
+                            declaration: false,
+                        },
+                    },
+                ],
+                exclude: /node_modules/,
+            },
+            {
+                test: /\.json$/,
+                loader: 'json-loader',
+            },
+        ],
+    },
+};