> ## 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.

# Architecture

> Overview of ComposableCoW's modular architecture with separated authorization, validation, and execution layers.

# Architecture

ComposableCoW is a modular system enabling conditional trading on CoW Protocol through separated authorization, validation, and execution layers.

## Core Components

### ComposableCoW Contract

Serves as the central coordinator, implementing `ISafeSignatureVerifier` to manage order authorization and validation. It tracks orders via two mechanisms:

* **Single orders** stored in a mapping indexed by owner and parameter hash
* **Merkle roots** for batch authorization of multiple orders

### ExtensibleFallbackHandler

Deployed at `0x2f55e8b20D0B9FEFA187AA7d00B6Cbe563605bF5`, it acts as a Safe fallback handler, delegating EIP-1271 signature verification to ComposableCoW through domain-specific verifiers.

### Order Handlers

Implement conditional logic by extending `IConditionalOrder`. The system includes:

* `IConditionalOrderGenerator` interface for handlers that generate tradeable orders
* `BaseConditionalOrder` abstract contract providing default verification logic
* Specialized handlers like TWAP for time-weighted average price orders

## Operational Flow

When a watchtower polls for tradeable orders, ComposableCoW:

1. Verifies authorization (single order or Merkle proof)
2. Calls the handler's `getTradeableOrder()` to generate an order
3. Validates against any configured swap guards
4. Returns the order and encoded signature

During settlement, CoW Protocol's `GPv2Settlement` calls `isValidSignature()` on the Safe, which delegates through `ExtensibleFallbackHandler` to ComposableCoW for final verification.

## Authorization Models

**Single Orders** suit small collections requiring frequent updates, while **Merkle Trees** optimize for larger static sets with O(log n) proof verification.

The system emphasizes stateless validation through view functions, reducing gas costs for unsuccessful order checks while maintaining security through handler validation of all parameters and generated order hashes.