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API Overview

The CoW Protocol BFF (Backend for Frontend) API provides a suite of services designed to enhance the user experience for frontend applications interacting with the CoW Protocol.

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Base URL

The API is accessible at: 
https://api.cow.fi
For local development: 
http://localhost:3001

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API Architecture

The BFF API is built on Fastify and provides endpoints organized into several key areas:
  • Tokens: Token information, pricing, and holder data
  • Accounts: User balances and allowances with real-time updates
  • Markets: Slippage tolerance recommendations for trading pairs
  • Simulation: Transaction simulation using Tenderly
  • Yield: Pool information and APR data from various DEX protocols
  • Affiliate: Affiliate program management and statistics
  • Notifications: Push notification subscriptions and delivery
  • Hooks: CoW Hooks analytics from Dune Analytics
  • Miscellaneous: Utility endpoints including API version and proxies

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Chain Support

The API supports multiple blockchain networks. Chain IDs are specified in the path for most endpoints:
  • 1 - Ethereum Mainnet
  • 100 - Gnosis Chain
  • 11155111 - Sepolia Testnet
Alternatively, you can use chain slugs:
  • mainnet - Ethereum Mainnet
  • gnosis - Gnosis Chain
  • sepolia - Sepolia Testnet

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Response Format

All API responses are in JSON format. Successful responses return the requested data with appropriate HTTP status codes (200, 201, etc.). Error responses include a message field describing the error: 
{
  "message": "Error description"
}

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Rate Limiting

The API implements caching headers to optimize performance. Check the Cache-Control header in responses to understand caching behavior.

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Getting Started

To get started with the API:
  1. Choose the appropriate endpoint for your use case
  2. Construct the request URL with the correct chain ID
  3. Make an HTTP request (GET, POST, etc.)
  4. Handle the JSON response

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API Documentation

Detailed documentation for each endpoint category is available in the following pages:

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Support

For issues or questions about the API, please refer to the CoW Protocol documentation or reach out to the development team.
Last modified on March 11, 2026