CoW Swap is the first trading interface built on top of CoW Protocol.

It allows you to buy and sell tokens using gasless orders that are settled peer-to-peer among its users or into any on-chain liquidity source while providing MEV protection.

| Platform | Link | | --------------------- | ------------------------------------------------------------------------------------------------------------- | | 🐮 CoW Swap 🐮 | swap.cow.fi | | CoW Swap (IPFS) | Every release is deployed automatically to IPFS (Releases) | | CoW Swap (ENS) | ens://cowswap.eth or (cowswap.eth.limo) | | CoW Protocol | cow.fi | | Docs | docs.cow.fi | | Governance (Snapshot) | snapshot.org/#/cow.eth | | Stats | dune.com/cowprotocol/cowswap | | X/Twitter | @CoWSwap | | Discord | discord.com/invite/cowprotocol | | Forum | forum.cow.fi |

🐮 Run CoW Swap

First install Dependencies:

yarn

Run

Start CoW Swap on http://localhost:3000

yarn start

Build

Build the project. The static files will be generated in the build folder.

yarn build

Unit testing

yarn test

🔎 Explorer

Start the Explorer on http://localhost:4200

Read more about the Explorer

Start

yarn start:explorer

Build

yarn build:explorer

🐄 cow.fi

Start CoW.fi on http://localhost:3001

Start

yarn start:cowfi

Build

yarn build:cowfi

🖼️ Widget Configurator

Start the Widget Configurator on http://127.0.0.1:4200/widget-configurator

# Start
yarn start:widget

# Build
yarn build:widget

🌌 Cosmos UI Library

Start the Cosmos UI Library on http://localhost:5000

yarn run cosmos

🤓 Development

Integration test

⚠️ To run the tests. Make sure you add the required environment varianbles to your .env.local file with:

• INTEGRATION_TEST_PRIVATE_KEY=<your-private-key>: Private key
• INTEGRATION_TESTS_INFURA_KEY=<your-infura-key>: Infura key

To launch it with our development server (so you have live-reloading):

yarn start
yarn cypress

Alternatively, you can build the project and launch the integration test.

yarn build
yarn integration-test

If we want to use the Cypress UI:

yarn build
yarn serve
yarn cypress

Build/test UI Library

CoW Swap has a library of reusable components.

yarn ui:build
yarn ui:test

Build

yarn build

Analyze CoW Swap bundle:

# Use one of the following templates: "sunburst" | "treemap" | "network" | "raw-data" | "list";
ANALYZE_BUNDLE=true ANALYZE_BUNDLE_TEMPLATE=sunburst yarn build

⚙️ Configuration

RPC Endpoints

You should set your own RPC endpoints.

One simple way to do this, is by defining your own REACT_APP_INFURA_KEY environment var.

Alternatively you can define the RPC URLs directly with the following environment variables:

REACT_APP_NETWORK_URL_1: https://...
REACT_APP_NETWORK_URL_11155111: https://...
REACT_APP_NETWORK_URL_100: https://...
REACT_APP_NETWORK_URL_42161: https://...
REACT_APP_NETWORK_URL_8453: https://...

Additionally, if you plan to run the integration tests locally you must define:

INTEGRATION_TESTS_INFURA_KEY: YOUR_INFURA_KEY
INTEGRATION_TESTS_PRIVATE_KEY: YOUR_TEST_WALLET_PRIVATE_KEY

Orderbook API Endpoints

Fee quote requests and posting orders are sent to the Orderbook API. This API has the responsibility of collecting orders and handing them to the solvers.

The reference implementation of the API is CoW Protocol Services.

The API endpoint is configured using the environment variable REACT_APP_ORDER_BOOK_URLS:

REACT_APP_ORDER_BOOK_URLS='{"1":"https://YOUR_HOST","100":"https://YOUR_HOST","5":"https://YOUR_HOST"}

BFF API Endpoints (Backend for Frontend)

The BFF API is a helper API that provides some additional data to the frontend. It is a API that is used to enhance the frontend experience enabling some features. It is not consider a required API for CoW Swap core functionality, the app will still allow the user to place order and will have some fallback logics in case this API is not available.

The reference implementation of the API is BFF (Backend For Frontend).

The API endpoint is configured using the environment variable REACT_APP_BFF_BASE_URL:

REACT_APP_BFF_BASE_URL=https://bff.cow.fi

CMS API Endpoints (Content Management System)

The CMS API is a helper API that provides some additional content to the frontend.

It is not considered a required API for CoW Swap core functionality, the app will still allow the user to place orders and will have some fallback logic in case this API is not available.

The reference implementation of the API is CMS API.

The API endpoint is configured using the environment variable REACT_APP_CMS_BASE_URL:

REACT_APP_CMS_BASE_URL=https://cms.cow.fi/api

Price feeds

CoW Swap tries to find the best price available on-chain using some price feeds.

All price feeds are enabled by default, but they can be individually disabled by using an environment variable:

| Name | Environment variable | Type | Description | | --------- | ------------------------------------ | ---------------------------- | ------------------------------------------------------------------------------------ | | 1inch | REACT_APP_PRICE_FEED_1INCH_ENABLED | boolean (default = true) | Paraswap price estimation. Used for all price estimations. | | 0x | REACT_APP_PRICE_FEED_0X_ENABLED | boolean (default = true) | 0x price estimation. Used for all price estimation. |

Metadata attached to orders (AppData)

The app will attach some metadata to all orders.

This metadata will be sent to the smart contract as a hexadecimal value in an order field called AppData. This value comes from hashing the content of a metadata JSON containing some information about the trade (using keccak256 on the UTF-8 bytes).

The format of the JSON follows the format defined in @cowprotocol/app-data.

To set your own AppData, change REACT_APP_FULL_APP_DATA_<environment> environment variable. For more details, check out the environment file (<.env>)

🔎 SEO

Sitemap

The sitemap can be found in <./public/sitemap.xml>

To update its content:

1. Edit the list of pages in <./src/sitemap.js>
2. Run yarn sitemap
3. Commit the changes to git

🔫 Troubleshooting

Service worker

In case of problems with the service worker cache you force a reset using emergency.js The plan:

1. const resetCacheInCaseOfEmergency = false - change false to true
2. Deploy a new version to production

emergency.js is not cached by browser and loaded before all.

Vercel preview build

Since this repo includes multiple apps, we do not want to build all of them on each PR because it causes long build queues in Vercel.
Some apps (see the list bellow) are not required to be built on each PR so we run them only a PR is labeled with a specific label. This label is defined in the project settings on Vercel in Settings/Git/Ignored Build Step script. For example, the label for the widget-configurator is preview-widget-cfg:

node tools/scripts/ignore-build-step.js --app=preview-widget-cfg

List of applications and their labels:

• widget-configurator: preview-widget-cfg
• cosmos: preview-cosmos
• sdk-tools: preview-sdk-tools

📚 Technical Documentation

1. Oveall Architecture
2. Amounts formatting
3. ABIs