1 files changed, 129 insertions, 0 deletions
diff --git a/contracts/core/README.md b/contracts/core/README.md
new file mode 100644
index 000000000..97a2816ff
--- /dev/null
+++ b/contracts/core/README.md
@@ -0,0 +1,129 @@
+## Contracts
+
+Smart contracts that implement the 0x protocol. Addresses of the deployed contracts can be found in the 0x [wiki](https://0xproject.com/wiki#Deployed-Addresses) or the [CHANGELOG](./CHANGELOG.json) of this package.
+
+## Usage
+
+Contracts that make up and interact with version 2.0.0 of the protocol can be found in the [contracts](./contracts) directory. The contents of this directory are broken down into the following subdirectories:
+
+*   [protocol](./contracts/protocol)
+    *   This directory contains the contracts that make up version 2.0.0. A full specification can be found [here](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md).
+*   [extensions](./contracts/extensions)
+    *   This directory contains contracts that interact with the 2.0.0 contracts and will be used in production, such as the [Forwarder](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/forwarder-specification.md) contract.
+*   [examples](./contracts/examples)
+    *   This directory contains example implementations of contracts that interact with the protocol but are _not_ intended for use in production. Examples include [filter](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#filter-contracts) contracts, a [Wallet](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#wallet) contract, and a [Validator](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#validator) contract, among others.
+*   [tokens](./contracts/tokens)
+    *   This directory contains implementations of different tokens and token standards, including [wETH](https://weth.io/), ZRX, [ERC20](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md), and [ERC721](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md).
+*   [multisig](./contracts/multisig)
+    *   This directory contains the [Gnosis MultiSigWallet](https://github.com/gnosis/MultiSigWallet) and a custom extension that adds a timelock to transactions within the MultiSigWallet.
+*   [utils](./contracts/utils)
+    *   This directory contains libraries and utils that are shared across all of the other directories.
+*   [test](./contracts/test)
+    *   This directory contains mocks and other contracts that are used solely for testing contracts within the other directories.
+
+## Bug bounty
+
+A bug bounty for the 2.0.0 contracts is ongoing! Instructions can be found [here](https://0xproject.com/wiki#Bug-Bounty).
+
+## Contributing
+
+We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
+
+Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
+
+### Install Dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+
+```bash
+yarn install
+```
+
+### Build
+
+To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
+
+```bash
+PKG=contracts yarn build
+```
+
+Or continuously rebuild on change:
+
+```bash
+PKG=contracts yarn watch
+```
+
+### Clean
+
+```bash
+yarn clean
+```
+
+### Lint
+
+```bash
+yarn lint
+```
+
+### Run Tests
+
+```bash
+yarn test
+```
+
+#### Testing options
+
+###### Revert stack traces
+
+If you want to see helpful stack traces (incl. line number, code snippet) for smart contract reverts, run the tests with:
+
+```
+yarn test:trace
+```
+
+**Note:** This currently slows down the test runs and is therefore not enabled by default.
+
+###### Backing Ethereum node
+
+By default, our tests run against an in-process [Ganache](https://github.com/trufflesuite/ganache-core) instance. In order to run the tests against [Geth](https://github.com/ethereum/go-ethereum), first follow the instructions in the README for the devnet package to start the devnet Geth node. Then run:
+
+```bash
+TEST_PROVIDER=geth yarn test
+```
+
+###### Code coverage
+
+In order to see the Solidity code coverage output generated by `@0x/sol-cov`, run:
+
+```
+yarn test:coverage
+```
+
+###### Gas profiler
+
+In order to profile the gas costs for a specific smart contract call/transaction, you can run the tests in `profiler` mode.
+
+**Note:** Traces emitted by ganache have incorrect gas costs so we recommend using Geth for profiling.
+
+```
+TEST_PROVIDER=geth yarn test:profiler
+```
+
+You'll see a warning that you need to explicitly enable and disable the profiler before and after the block of code you want to profile.
+
+```typescript
+import { profiler } from './utils/profiler';
+profiler.start();
+// Some call to a smart contract
+profiler.stop();
+```
+
+Without explicitly starting and stopping the profiler, the profiler output will be too busy, and therefore unusable.