ISwapGuard

Core Function

The interface requires a single verify() function that evaluates whether an order meets security criteria before settlement. This function receives:

Parameter	Type	Description
`order`	`GPv2Order.Data`	The CoW Protocol order data
`ctx`	`bytes32`	Context identifier (either `bytes32(0)` for merkle trees or a hash for cabinet lookups)
`params`	`ConditionalOrderParams`	Programmatic order parameters
`offchainInput`	`bytes`	Optional off-chain verification input

The function returns a boolean indicating approval.

Implementation Examples

ReceiverLock

Restricts orders to self-transfers only, preventing fund redirection by ensuring the receiver is set to address(0).

TokenWhitelistGuard

Maintains an approved token list, validating both the sell and buy tokens against this whitelist.

AmountLimitGuard

Enforces maximum trade sizes by checking the sell amount against a configured limit.

Key Requirements

Implementations should inherit from BaseSwapGuard for proper ERC-165 interface support

Verification logic must remain stateless, deterministic, and gas-efficient since it executes during order validation

Guards represent security-critical components requiring thorough testing before production deployment. Guards cannot prevent malicious order handlers from being used.

Contracts

Hooks Trampoline

Composable CoW

Contracts SDK

Flash Loan Router

ISwapGuard

Core Function

Implementation Examples

ReceiverLock

TokenWhitelistGuard

AmountLimitGuard

Key Requirements

​ISwapGuard

​Core Function

​Implementation Examples

​ReceiverLock

​TokenWhitelistGuard

​AmountLimitGuard

​Key Requirements

ISwapGuard

Core Function

Implementation Examples

ReceiverLock

TokenWhitelistGuard

AmountLimitGuard

Key Requirements