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CCTP

How Circle's Cross-Chain Transfer Protocol moves native USDC between chains by burning it on one and minting it on the other.

Xebra does not move USDC itself. It prices transfers, builds the transactions, and takes a fee on some routes. The movement is Circle's Cross-Chain Transfer Protocol (CCTP), version 2.

Burn, attest, mint

Every transfer has three steps.

Burn

The sender's wallet calls Circle's TokenMessenger on the chain the transfer starts on. Circle burns the USDC and emits a message naming the destination chain, the recipient and the amount.

Attest

Circle waits until the source chain has finalised the burn, then signs an attestation: a statement that this USDC was burned for this recipient on this destination. The message and its attestation are public. Anyone can read them from Circle's attestation service (Iris).

Mint

Someone submits the message and attestation to Circle's MessageTransmitter on the destination. It checks Circle's signature and mints the same amount of native USDC to the recipient, less any fee the burn allowed. On most routes Circle's own Forwarding Service does this step; see Forwarding.

The USDC that arrives is minted by Circle on the destination chain. It is the same native USDC as any other USDC there, not a wrapped or bridged token. There is no liquidity pool and no one holds the funds in between.

Domains

CCTP names chains by a numeric domain, not by chain id. A few that matter here: Solana is 5, Sui is 8, Arc is 26 and Stellar is 27. The API and SDK use chain names ("stellar", "base") and translate to domains for you. @xebra/sdk/core exports the full table as EVM_CHAINS and STELLAR_CCTP_DOMAIN.

Standard and Fast

CCTP V2 offers two finality levels, which the API calls speeds:

  • Standard (finalityThreshold 2000). Circle attests once the source chain has finalised the burn. Circle charges no transfer fee for this. Its attestation never expires.
  • Fast (finalityThreshold 1000). Circle attests sooner, before full finality, and charges a small fee proportional to the amount. Only some source chains offer it. A Fast attestation can expire before it is used; see Recovery.

Stellar and Sui offer Standard only. Which speeds a route has is listed by GET /v1/routes, and GET /v1/quote prices one speed at a time.

How long it takes

Most of the time is the source chain reaching finality and Circle attesting. Circle's own figures for a Standard burn range from under a minute on chains with fast finality to about 15 to 30 minutes on others (as recorded in the SDK's chain table, EVM_CHAINS[...].standardEta, on 2026-11-12). Delivery after attestation usually adds seconds to a few minutes. waitForDelivery polls until the transfer settles.

Who can mint

A CCTP message can name a destinationCaller: the only address allowed to submit the mint.

  • Burns out of Stellar and out of EVM chains leave it empty. Once Circle has attested the burn, anyone can submit the mint, so a transfer never depends on Xebra being online.
  • Burns from Sui to Stellar name Circle's CctpForwarder on Stellar, which Circle requires for that route. The forwarder's mint_and_forward function is itself public, so anyone can still finish the transfer.

Either way the recipient and amount are fixed inside the attested message. Whoever submits the mint pays the destination's network fee; they cannot change who receives the USDC.

Quickstart

Price a transfer, build it for your user's wallet, and follow it to delivery, in about five minutes.

Forwarding

Who submits the mint on the destination chain, who pays for it, and what happens when they do not.

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Burn, attest, mintBurnAttestMintDomainsStandard and FastHow long it takesWho can mintRelated