CCTP Starknet contracts and interfaces

Contracts for CCTP support on the Starknet blockchain

Overview

Starknet CCTP contracts are written in Cairo and run on a non-EVM zk-rollup. Transactions executed on Starknet are batched and proven using STARK proofs, which are then posted to Ethereum L1. This design allows Starknet to inherit Ethereum’s security while offering higher throughput and lower fees.

To align with Starknet’s architecture while keeping parity with EVM chains, CCTP uses two contracts:

• TokenMessengerMinterV2: consolidates the responsibilities of TokenMessengerV2 (burn + send) and TokenMinterV2 (receive + mint).
• MessageTransmitterV2: provides the messaging layer that emits or receives attested messages and delivers them to TokenMessengerMinterV2.

This mirrors how other non-EVM deployments (for example, Solana) combine messenger and minter logic while preserving behavior with the EVM equivalents.

Mainnet contract addresses

Contract	Domain	Address
TokenMessengerMinterV2	25	0x07d421B9cA8aA32DF259965cDA8ACb93F7599F69209A41872AE84638B2A20F2a
MessageTransmitterV2	25	0x02EBB5777B6dD8B26ea11D68Fdf1D2c85cD2099335328Be845a28c77A8AEf183

Testnet contract addresses

Contract	Domain	Address
TokenMessengerMinterV2	25	0x04bDdE1E09a4B09a2F95d893D94a967b7717eB85A3f6dEcA8c080Ee01fBc3370
MessageTransmitterV2	25	0x04db7926C64f1f32a840F3Fa95cB551f3801a3600Bae87aF87807A54DCE12Fe8

CCTP interface

• TokenMessengerMinterV2: initiates crosschain burns and mints tokens upon attested message receipt.
• MessageTransmitterV2: emits messages, verifies attestations, and routes verified messages to the recipient contract.

TokenMessengerMinterV2 interface

The TokenMessengerMinterV2 contract consolidates the roles of both TokenMessengerV2 and TokenMinterV2 found on EVM chains. It handles USDC burns, message emission, and token minting once crosschain messages are attested by Circle’s Iris service.

Function	Description	Notes
deposit_for_burn	Burns USDC and emits a crosschain message for minting on another domain.	Standard CCTP transfer initiation.
deposit_for_burn_with_hook	Same as deposit_for_burn, but attaches custom metadata (hook_data).	Used for programmable transfers.
handle_receive_finalized_message	Mints USDC upon receiving a fully finalized message.	Called by MessageTransmitterV2.
handle_receive_unfinalized_message	Processes partially finalized (“Fast Burn”) messages.	Enables faster crosschain transfers.
message_body_version	Returns supported message format version.	Used for compatibility checks.
local_message_transmitter	Returns the linked MessageTransmitterV2 address.	Must match configured domain transmitter.

MessageTransmitterV2 interface

The MessageTransmitterV2 contract provides the core messaging layer for CCTP on Starknet. It is responsible for emitting, receiving, and validating crosschain messages, enforcing attestation rules, and ensuring message uniqueness.

Function	Description	Notes
send_message	Sends a crosschain message with specified domain, recipient, and message body.	Core function for outgoing CCTP messages.
receive_message	Validates a message and its attestation; delivers message body to the recipient.	Called by an offchain forwarding service with an attestation from Circle to complete the transfer.
get_max_message_body_size	Returns the maximum allowed message size.	Used by offchain components for validation.
is_nonce_used	Checks if a message nonce has been processed already.	Prevents message replay.
get_local_domain	Returns this contract’s domain ID.	Expected to be 25 for Starknet.
get_version	Returns protocol version supported by this transmitter.	Used by Iris attestation service.