# CCTP FAQ
What is CCTP?
Cross-Chain Transfer Protocol (CCTP) is a permissionless onchain utility that facilitates USDC transfers between blockchains via native burning and minting. With CCTP, USDC is effectively teleported from one blockchain to another.
How does CCTP differ from lock-and-mint bridging?
Lock-and-mint bridges are applications that lock a user’s native USDC within a smart contract on a source chain and then mint a synthetic or bridged form of USDC on a destination chain. This process incurs additional trust assumptions and can result in poor UX due to the fragmentation of liquidity.
In contrast, CCTP enables USDC to move securely 1:1 between blockchains via a native burn-and-mint process. The result is greater capital efficiency and unified liquidity with no creation of bridged forms of USDC. As a low-level primitive, CCTP can be embedded within existing bridge apps to replace their lock-and-mint functionality.
How does CCTP differ from liquidity pool bridging?
Liquidity pool bridges are applications that hold large pools of USDC on a source chain and a destination chain in order to facilitate cross-chain swaps for end users. This process incurs additional trust assumptions and fees associated with the liquidity tied up on each chain.
In contrast, CCTP enables USDC to move securely 1:1 between blockchains via a native burn-and-mint process. The result is greater capital efficiency and unified liquidity without the need for large pools of USDC tokens. As a low-level primitive, CCTP can be embedded within existing bridge apps to replace their liquidity pool functionality. Alternatively, CCTP could be used by the bridge provider to programmatically rebalance their liquidity pools behind the scenes and reduce operational costs.
Who is CCTP designed for?
CCTP is a permissionless protocol that you can integrate into your app, bridge, exchange, or wallet. It provides core infrastructure for cross-chain transfers. You can use CCTP to enable advanced cross-chain functionality at faster speeds and enhanced composability, or continue to use standard cross-chain functionality at standard speeds. For details, see the [CCTP overview](https://developers.circle.com/cctp).
Does CCTP require signing up with Circle?
No, CCTP is permissionless, which means any developer can integrate via [Circle’s docs](https://developers.circle.com/cctp) and [GitHub repository](https://github.com/circlefin).
What are the fees associated with cross-chain transfers via CCTP?
There is a gas fee charged on the source blockchain and on the destination blockchain. The app that integrates with CCTP is responsible for determining how gas fees are handled.
For fast transfers, an additional fee is collected when the stablecoin is minted on the destination chain. The fee is based on the amount minted. For more information, see the [CCTP fees](broken://pages/bac7c1a53b3bea89fbae2edfa8de2d0ac977aa43#fees) section.
What is the Fast Transfer Allowance in CCTP?
Circle’s Fast Transfer Allowance limits the total amount of USDC that can be minted using CCTP Fast Transfer before the corresponding burns on source chains reach finality. This mechanism caps the aggregate value of in-flight transfers awaiting hard finality, helping mitigate risk while enabling faster minting on destination chains. The allowance applies only to CCTP Fast Transfer and ensures that system-wide exposure to non-finalized burns remains within a defined threshold.
When will CCTP be available on additional chains?
CCTP is available on multiple blockchains, with more chains to be added over time. For the latest list, see [CCTP supported blockchains](/chainaiswap-docs/cross-chain-transfer-protocol/cctp-supported-chains-and-domains.md).
Can't I use Circle Mint to move USDC across chains? What about a centralized exchange?
Yes, Circle Mint is capable of moving USDC natively across chains. However, Circle Mint is a commercial product that is only available to qualified businesses approved by Circle.
Centralized exchanges typically hold various native forms of USDC liquidity on their platforms. Users with an account at a centralized exchange can deposit USDC (native to a given chain) into their exchange wallet, and then withdraw USDC (native to a different chain) to their external wallet.
In contrast, CCTP is permissionless. This means it’s accessible to any developer to seamlessly integrate into their apps and does not require onboarding to Circle. End users can move USDC through a CCTP-enabled app to any supported blockchain at any time. Developers can also compose new onchain experiences on top of CCTP within their apps.
How does a given quantity of USDC burned on the source chain become successfully minted on the destination chain?
When USDC is burned on the source chain, the event is automatically observed by Circle’s Attestation Service. The app facilitating the burn of USDC is responsible for fetching the signed attestation from Circle, which then enables CCTP to mint USDC on the destination chain.
Have the CCTP smart contracts undergone security audits?
Yes. The CCTP smart contracts have been independently audited by third-party security firms:
* CCTP was audited by [ChainSecurity (PDF)](https://6778953.fs1.hubspotusercontent-na1.net/hubfs/6778953/PDFs/ChainSecurity_Circle_CCTP_V2_audit%20\(1\).pdf) and [OtterSec (PDF)](https://6778953.fs1.hubspotusercontent-na1.net/hubfs/6778953/PDFs/public_evm_cctp_audit_final%20\(2\).pdf).
* CCTP (with Standard Transfer fee switch) was audited by [ChainSecurity (PDF)](https://6778953.fs1.hubspotusercontent-na1.net/hubfs/6778953/CCTP/ChainSecurity_Circle_CCTP_audit_2025-07.pdf).
* CCTP V1 (Legacy) was audited by [ChainSecurity (PDF)](https://6778953.fs1.hubspotusercontent-na1.net/hubfs/6778953/CCTP/ChainSecurity_Circle_Circle_EVM_Bridge_audit.pdf) and [Halborn (PDF)](https://6778953.fs1.hubspotusercontent-na1.net/hubfs/6778953/CCTP/Circle_Internet_Financial_EVM_Bridge_Smart_Contract_Security_Audit_Report_Halborn_Final.pdf).
Refer to the linked reports for detailed findings and audit results.
What happens if Circle's Attestation Service is unresponsive?
While its unavailability would temporarily preclude new burn messages from being signed, we anticipate robust uptime and availability similar to how our existing minting services operate today. You can always check [status.circle.com](https://status.circle.com/) for real-time updates on service availability.
How does CCTP affect existing bridged forms of USDC?
CCTP has no direct impact upon existing bridged forms of USDC.
How does CCTP affect Circle's plans to launch USDC on more blockchains?
Circle’s plans to bring USDC natively to more blockchain networks remain the same and will continue to grow. We envision CCTP establishing USDC as a universal liquidity layer for the Internet that is accessible to all.
For more information, see the [CCTP Technical Guide](broken://pages/bac7c1a53b3bea89fbae2edfa8de2d0ac977aa43).
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