Unite the ecosystem
async function usdcCrossChainTransfer(amount: number, destinationAddress: string) {
// Deposit USDC tokens for burn and obtain transaction hash
const burnUsdcTx = await ethTokenMessengerContract.depositForBurn(amount, AVAX_DESTINATION_DOMAIN, destinationAddress, USDC_ETH_CONTRACT_ADDRESS).send();
// Extract message from burn transaction and calculate messageHash
const { messageBytes, messageHash } = extractMessageAndHash(burnUsdcTx);
// Retrieve attestation for message hash and mint USDC on AVAX tokens on the destination chain
const { attestation } = await fetch(`https://iris-api-sandbox.circle.com/attestations/${messageHash}`).json();
// Mint the USDC on AVAX tokens on the destination chain using the burn transaction message and attestation
await avaxMessageTransmitterContract.receiveMessage(messageBytes, attestation).send();
}
Maximum capital efficiency
CCTP solves the issues of liquidity fragmentation and poor user experiences caused by unofficial, bridged forms of USDC floating around the ecosystem.
Apps built on CCTP can essentially teleport USDC from one blockchain to another, providing users with a highly secure and capital-efficient way to transact in a multi-chain world.
Permissionless and composable
CCTP is a low-level primitive for developers to leverage and extend. Embed the protocol within your app, wallet, or bridge, and enable users to move any amount of USDC to any supported ecosystem.
In many cases, your app can inherit CCTP functionality from a bridge or wallet SDK that’s already part of your stack.
How it works
Programmatic burning and minting
// Call the MessageTransmitter
receiveMessage function on the destination chain
const receiveTx = await)
avaxMessageTransmitterContract.receiveMessage(receivingMessageBytes, signature);
Complete transfer on destination chain
Your app uses the attestation to trigger the minting of USDC. The specified amount of USDC is minted on the destination chain and sent to the recipient wallet address.
// Extract the message from the emitted MessageSent event
const transactionReceipt = await web3.eth.getTransactionReceipt(burnTx.transactionHash);
const eventTopic = web3.utils.keccak256('MessageSent(bytes)')
const log = transactionReceipt.logs.find((l) => l.topics[0] === eventTopic)
const messageBytes = web3.eth.abi.decodeParameters(['bytes'])
const messageHash = web3.utils.keccak256(messageBytes);
// Fetch the attestation from Circle's API
let attestationResponse = {status: 'pending'};
while (attestationResponse.status != 'complete') {
attestationResponse = (await fetch('https://iris-api-sandbox.circle.com/attestations/${messageHash}')).json();
// Wait 2 seconds in between calls
await new Promise(r => setTimeout(r, 2000));
}
Fetch signed attestation from Circle
Circle observes and attests to the burn event on the source chain. Your app requests the attestation from Circle, which provides authorization to mint the specified amount of USDC on the destination chain.
// Call the TokenMessenger depositForBurn
const transactionReceipt = await web3.eth.getTransactionReceipt(burnTx.transactionHash);
function on the source chain
const burnTx = await
ethTokenMessengerContract.methods.depositForBurn(amount,
AVAX_DESTINATION_DOMAIN, destinationAddressInBytes32,
USDC_ETH_CONTRACT_ADDRESS).send();
Initiate transfer on source chain
A user accesses your app to initiate a transfer of USDC from one blockchain to another, and specifies the recipient wallet address on the destination chain. Your app facilitates a burn of the specified amount of USDC on the source chain.
Ecosystem
Trusted by the community
Wallets
Bridges
Partner SDKs
Provide cross-chain swaps
Enable users to swap between digital assets that live on different blockchains, even across L2 rollups (e.g. ARB on Arbitrum for OP on OP Mainnet). In a completely automated way, ARB can be swapped for USDC on Arbitrum, routed by CCTP to OP Mainnet, and swapped for OP.
Enable cross-chain deposits
Allow users to utilize USDC on Ethereum to open a trading position on a decentralized exchange on Base. Because CCTP can route USDC between blockchains behind the scenes, users can onboard to a new app and never need to switch wallets or think about which blockchain they’re holding USDC.
Offer cross-chain purchases
With one click, a user can utilize USDC on Polygon PoS to buy an Avalanche-based NFT on Uniswap and list it for sale on OpenSea. When the user initiates the transaction, CCTP routes their USDC from Polygon PoS to Avalanche to purchase the NFT from Uniswap, then opens the listing on OpenSea.
Optimize cross-chain treasury
Marketplace apps can accept USDC payments on multiple blockchains and use CCTP for bulk transfers behind the scenes. Exchanges and liquidity pool bridges can use CCTP to securely rebalance USDC holdings per blockchain to reduce operational costs and meet withdrawal demand on the fly.