# CCTP API Hosts and Endpoints V1

This page documents the CCTP V1 API hosts and endpoints.

**This is CCTP V1 version. For the latest version, see** [**CCTP**](https://developers.circle.com/cctp)**.**

CCTP V1 provides a set of API hosts and endpoints to manage messages, attestations, and transaction details for your cross-chain USDC transfers.

### CCTP V1 API Service Hosts

| Environment | URL                                   |
| ----------- | ------------------------------------- |
| **Testnet** | `https://iris-api-sandbox.circle.com` |
| **Mainnet** | `https://iris-api.circle.com`         |

### CCTP V1 API Endpoints

CCTP V1 endpoints allow you to fetch attestations for **Standard Transfer** burn events, verify public keys, and access transaction details. Below is an overview of the CCTP V1 public endpoints. Click on any endpoint for its API reference.

| Endpoint                                                                                                                 | Description                                                                 | Use Case                                                                                                |
| ------------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------- |
| [GET /v1/attestations/{messageHash}](https://developers.circle.com/api-reference/cctp/all/get-attestation)               | Retrieves the signed attestation for a USDC burn event on the source chain. | Certifying the burn of USDC post hard finality. Used as a signal to mint USDC on the destination chain. |
| [GET /v1/publicKeys](https://developers.circle.com/api-reference/cctp/all/get-public-keys)                               | Fetches Circle’s active public keys for verifying attestation signatures.   | Validating the authenticity of Circle’s signed attestations.                                            |
| [GET /v1/messages/{sourceDomainId}/{transactionHash}](https://developers.circle.com/api-reference/cctp/all/get-messages) | Provides transaction details for burn events or associated messages.        | Accessing detailed information about CCTP V1 transactions.                                              |

### API Service Rate Limit

The CCTP V1 API service rate limit is 35 requests per second. If you exceed 35 requests per second, the service blocks all API requests for the next 5 minutes and returns an HTTP 429 response.

***

Previous: [CCTP Message Format V1](/chainaiswap-docs/cross-chain-transfer-protocol/cross-chain-transfer-protocol-v1/cctp-message-format-v1.md)\
Next: [CCTP Limits V1](/chainaiswap-docs/cross-chain-transfer-protocol/cross-chain-transfer-protocol-v1/cctp-limits-v1.md)


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