CCIP v2.0.0 ICrossChainVerifierV1 API Reference

ICrossChainVerifierV1 defines the lifecycle interface for Cross-Chain Verifier (CCV) implementations.

It standardizes:

• source-side verifier data generation (forwardToVerifier)
• destination-side message validation (verifyMessage)
• verification fee calculation (getFee)

All CCV implementations must follow this interface to ensure consistent cross-chain validation behavior.

This interface defines functions implemented by protocol contracts and is not typically used directly by applications.

Usage Boundary

You do not call this interface directly.

• OnRamp components call forwardToVerifier during message submission.
• OffRamp components call verifyMessage during message validation.
• Routing components call getFee to calculate verification cost.
• You implement this interface when building custom verifier logic.

Contract

interfaces/ICrossChainVerifierV1.sol

Import

import {ICrossChainVerifierV1} from "chainlink-ccip/interfaces/ICrossChainVerifierV1.sol";

If you have not installed the package:

npm install @chainlink/contracts-ccip@2.0.0

Inheritance

• IERC165

External API

verifyMessage

function verifyMessage(
  MessageV1Codec.MessageV1 memory message,
  bytes32 messageId,
  bytes memory verifierResults
) external

Validates a message on the destination chain using verifier-specific data.

• Reverts if validation fails.

getFee

function getFee(
  uint64 destChainSelector,
  Client.EVM2AnyMessage memory message,
  bytes memory extraArgs,
  bytes4 requestedFinalityConfig
) external view returns (
  uint16 feeUSDCents,
  uint32 gasForVerification,
  uint32 payloadSizeBytes
)

Returns the verification fee and resource requirements for processing a message.

Returns:

forwardToVerifier

function forwardToVerifier(
  MessageV1Codec.MessageV1 calldata message,
  bytes32 messageId,
  address feeToken,
  uint256 feeTokenAmount,
  bytes calldata verifierArgs
) external returns (bytes memory verifierData)

Produces verifier-specific data on the source chain for later destination-side validation.

• Output is passed to the destination chain and consumed by verifyMessage.

Returns:

getStorageLocations

function getStorageLocations() external view returns (string[] memory)

Returns off-chain storage locations used by the verifier implementation.

Returns:

Notes

• verifyMessage must be called with verifier data produced by forwardToVerifier.
• Message data and verifier results must match exactly between source and destination chains.
• messageId is the canonical identifier passed through the verifier interface. Implementations may also derive or validate a message hash internally.
• For a given message and verifier configuration, forwardToVerifier should produce deterministic verifier data.
• getFee should be called with the same message parameters that will be used for verifier execution.
• Verification will revert if verifier data is invalid, mismatched, or incomplete.
• Verifiers act as execution gates: messages are processed only if validation succeeds.

Related Interfaces & Contracts

• ICrossChainVerifierResolver
• BaseVerifier
• CommitteeVerifier
• CCTPVerifier
• LombardVerifier
• MessageV1Codec
• Client