> ## Documentation Index
> Fetch the complete documentation index at: https://circle-devdocs-test-ai-codegen-component.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# CCTP FAQ

> Learn why Circle created CCTP and how it differs from traditional bridging.

<AccordionGroup>
  <Accordion title="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.
  </Accordion>

  <Accordion title="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.
  </Accordion>

  <Accordion title="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.
  </Accordion>

  <Accordion title="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](/cctp).
  </Accordion>

  <Accordion title="Does CCTP require signing up with Circle?">
    No, CCTP is permissionless, which means any developer can integrate via
    [Circle's docs](/cctp) and [GitHub repository](https://github.com/circlefin).
  </Accordion>

  <Accordion title="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
    [product fee schedule](https://help.circle.com/s/article/Cross-Chain-Transfer-Protocol-product-fee-schedule?language=en_US\&category=Fees_and_Billing)
    on the Circle Help Center.
  </Accordion>

  <Accordion title="What is the Fast Transfer Allowance in CCTP?">
    Circle's Fast Transfer Allowance uses offchain funds to overcollateralize
    supported stablecoins, enabling message attestation before finalization. This
    mechanism is only used for CCTP fast transfers, and ensures that the stablecoin
    remains fully reserved in the event of a mint for which the associated source
    chain burn is affected by a reorg.
  </Accordion>

  <Accordion title="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](/cctp/cctp-supported-blockchains).
  </Accordion>

  <Accordion title="Can a blockchain support multiple CCTP versions?">
    Yes, CCTP versions can coexist on the same blockchain. For example, CCTP V2 and
    CCTP V1 are available on multiple chains. CCTP V2 also supports standard
    transfers, so there's no need to use a legacy version for this functionality.
  </Accordion>

  <Accordion title="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.
  </Accordion>

  <Accordion title="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.
  </Accordion>

  <Accordion title="Have the CCTP smart contracts undergone security audits?">
    Yes. The CCTP smart contracts have been independently audited by third-party
    security firms:

    * CCTP V2 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 V2 (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 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.
  </Accordion>

  <Accordion title="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.
  </Accordion>

  <Accordion title="How does CCTP affect existing bridged forms of USDC?">
    CCTP has no direct impact upon existing bridged forms of USDC.
  </Accordion>

  <Accordion title="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.
  </Accordion>
</AccordionGroup>

***

<br />

**WHAT'S NEXT**

* [Transfer USDC on testnet from Ethereum to Avalanche using CCTP <Icon icon="arrow-right" />](/cctp/transfer-usdc-on-testnet-from-ethereum-to-avalanche)