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.