# CCTP Starknet Contracts and Interfaces

### Overview

Starknet CCTP contracts are written in Cairo and run on a non-EVM zk-rollup. 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.

### Testnet contract addresses

| Contract                 | [Domain](/chainaiswap-docs/cross-chain-transfer-protocol/cctp-supported-chains-and-domains.md#cctp-supported-domains) | Address                                                                                                                                                                            |
| ------------------------ | --------------------------------------------------------------------------------------------------------------------: | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `TokenMessengerMinterV2` |                                                                                                                    25 | [`0x04bDdE1E09a4B09a2F95d893D94a967b7717eB85A3f6dEcA8c080Ee01fBc3370`](https://sepolia.voyager.online/contract/0x04bDdE1E09a4B09a2F95d893D94a967b7717eB85A3f6dEcA8c080Ee01fBc3370) |
| `MessageTransmitterV2`   |                                                                                                                    25 | [`0x04db7926C64f1f32a840F3Fa95cB551f3801a3600Bae87aF87807A54DCE12Fe8`](https://sepolia.voyager.online/contract/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 relayer 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.                                                       |

Previous: [CCTP Solana Programs and Interfaces](/chainaiswap-docs/cross-chain-transfer-protocol/cctp-solana-programs-and-interfaces.md)\
Next: [CCTP Block Confirmations](/chainaiswap-docs/cross-chain-transfer-protocol/cctp-block-confirmations.md)

Responses are generated using AI and may contain mistakes.


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