> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cow.bleu.builders/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Overview of CoW Protocol BFF (Backend For Frontend), a TypeScript-based service collection powering CoW Swap and related applications

# Introduction

The CoW Protocol BFF is a comprehensive collection of TypeScript-based backend services designed to power the CoW Swap frontend and other CoW Protocol applications.

## Core Capabilities

The platform offers six main feature categories:

1. **Multi-Chain Support** - Token pricing and balance data across twelve networks (Ethereum, Gnosis Chain, Arbitrum One, Base, Polygon, Avalanche, BNB Chain, Linea, Plasma, Ink, and Sepolia testnet)

2. **Real-Time Updates** - Server-Sent Events delivering live wallet balance information for multiple tokens simultaneously

3. **Notifications** - Telegram integration with RabbitMQ messaging for order status alerts

4. **Market Analysis** - Dynamic slippage calculations based on volatility patterns

5. **Transaction Preview** - Tenderly-powered simulation tools for trade outcome forecasting

6. **Yield Tracking** - Multi-protocol DeFi opportunity aggregation and comparison

## Technical Foundation

The architecture utilizes:

* **Fastify** - HTTP framework
* **NX** - Monorepo management
* **PostgreSQL with TypeORM** - Data persistence
* **Redis** - Caching
* **RabbitMQ** - Asynchronous messaging
* **Ethers.js/Viem** - Blockchain interactions

## Service Components

Four primary applications form the system:

* **API Service** - REST endpoints
* **Notification Producer** - Event monitoring
* **Telegram Service** - Message delivery
* **TWAP Service** - Price calculations

These are supplemented by shared libraries for repositories, business logic, and utilities.