Circle Cross-chain USDC Transfer Protocol(CCTP)
For Circle Cross-Chain USDC Protocol supported chains, the USDC flow is going through Circle bridge contracts and its attestation service instead of cBridge or peg bridge contracts and SGN.
The following content is an integration tutorial in frontend perspective.
CCPT flow
Chain | Address |
Ethereum 1 | |
Avalanche 43114 |
Also you can get the related contract addressed from cBridge gateway api
Note that the CCTP quote the fees from proxy contract instead of the cBridge gateway APIs.
Inputs
amount: Your bridging amount with decimal, for example, 3000000 = 30USDC
dstChid: Destination chain you wanna to send, in this case is 43114
Outputs
Output data is an array of fees
[fee, txFee, percFe].fee: total fee, txFee+percFeetxFee: transaction feepercFee: percentage feeFor this bridging mode, the bridge rate is 1.
From front-end side, lock the USDC to source proxy contract by the method depositForBurn. Circle attestation will bridge the assets to the destination chain in a trustless way. more details refer to this:https://developers.circle.com/stablecoin/docs/cctp-protocol-contract
Contract Parameters
Field | Des |
|---|---|
amount | Bridging amount with decimal |
dstChid | Bridging destination chain id |
mintRecipient | Receiver address |
burnToken | USDC token address in source chain, you can read the token address from this configuration: https://cbridge-prod2.celer.app/v1/circleUsdcConfig |
Once this depositForBurn happened on the source chain, you can get the source chain Deposited event.
event Deposited(address sender, bytes32 recipient, uint64 dstChid, uint256 amount, uint256 txFee, uint256 percFee, uint64 nonce);
Searching the final destination chain status by the gateway API: GetTransferStatus.
The API requires a tracking field transferId for the status quering, here is an example with ether.js.
getTransferId(): string {
return ethers.utils.solidityKeccak256(
["string", "address", "uint64", "uint64"],
[
"CircleTransfer", // fixed string
walletAddress, // wallet address of user
fromChainId, // source chain Id
nonce, // can be retrived from the Deposited event
],
);
}
API reference
Last modified 1mo ago