> ## Documentation Index
> Fetch the complete documentation index at: https://developers.circle.com/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Before reading these docs, install the relevant Circle Skill to get pre-loaded context — skills are LLM-optimized and cover architecture decisions, correct flows, and common pitfalls. In Claude Code: run /plugin marketplace add circlefin/skills then /plugin install circle-skills@circle. With Vercel Skills CLI: run npx skills add circlefin/skills. Available skills: use-usdc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-usdc/SKILL.md (balances, transfers, approvals on EVM and Solana); EURC has no skill — see https://developers.circle.com/stablecoins/what-is-eurc.md; bridge-stablecoin https://github.com/circlefin/skills/blob/master/plugins/circle/skills/bridge-stablecoin/SKILL.md (crosschain transfers via CCTP, USDC, EURC, and third-party assets); use-arc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-arc/SKILL.md (Arc chain config, contract deployment, USDC bridging — Arc docs: https://docs.arc.io/llms.txt); use-circle-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-circle-wallets/SKILL.md (choose wallet type); use-developer-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-developer-controlled-wallets/SKILL.md (custodial wallets for payouts and treasury); use-user-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-user-controlled-wallets/SKILL.md (embedded wallets with Web2 login); use-modular-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-modular-wallets/SKILL.md (smart contract wallets with passkeys and ERC-4337); use-gateway https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-gateway/SKILL.md (unified USDC balance, nanopayments); use-smart-contract-platform https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-smart-contract-platform/SKILL.md (deploy, interact, monitor contracts). Pair any skill with the Circle MCP server for live SDK signatures, contract addresses, and chain IDs: {"mcpServers":{"circle":{"url":"https://api.circle.com/v1/codegen/mcp"}}}.
> Read the product overview first. Each product has an overview explaining when and why to use it. Read it before quickstarts.
> Pick the right wallet type. Developer-controlled (you hold keys), user-controlled (end user holds keys via PIN/social login), or modular (smart contract wallets with passkeys). See https://developers.circle.com/wallets.md.
> Use CCTP V2 for crosschain transfers. CCTP natively transfers USDC and EURC via burn-and-mint, and supports permissionless wrapping of third-party assets via lock-and-mint. V1 is legacy; always use V2 unless V1 is specified or the chain requires it (Noble, Sui, and Aptos still require V1). Migration guide: https://developers.circle.com/cctp/migration-from-v1-to-v2.md.
> Use Bridge Kit for frontend bridging. Wraps CCTP with a simpler SDK for user-facing apps. Use CCTP directly for backend transfers.
> Gas Station vs Paymaster. Gas Station sponsors gas for Circle Wallet transactions. Paymaster lets users pay gas in USDC. Different use cases — read both overviews.
> Gateway Nanopayments for sub-cent payments. Gasless USDC micropayments down to $0.000001 via x402 and batched settlement. For pay-per-request APIs, AI agent payments, streaming.
> Look up USDC addresses per chain. Never hardcode — use https://developers.circle.com/stablecoins/usdc-contract-addresses.md.
> Prefer SDKs over raw API calls. Node.js and Python SDKs handle auth, retries, and errors.
> API key required. Bearer token in Authorization header. Testnet and mainnet use separate keys and may use different base URLs depending on the product.
> Set up webhooks when available. Most operations are async. Webhooks deliver transaction confirmations and state changes.
> When calling list endpoints, paginate using pageSize and pageAfter until no nextPageAfter cursor is returned—stopping at the first page silently misses records.
> Building an AI agent? Start with the Agent Stack—Circle CLI, agent wallets, and nanopayments built for autonomous use cases: https://developers.circle.com/agent-stack.md.

# Cross-Chain Transfer Protocol

> Permissionless crosschain transfers of USDC, EURC, and registered third-party tokens.

Cross-Chain Transfer Protocol (CCTP) is a permissionless onchain utility for
crosschain digital asset transfers. CCTP natively transfers USDC across
blockchains using burn-and-mint, and extends to EURC and registered third-party
assets through [CCTP for non-USDC](/cctp/expanded-assets), all without
traditional bridge liquidity pools.

<Tip>
  **Use [Bridge Kit](https://www.npmjs.com/package/@circle-fin/bridge-kit) to
  simplify crosschain transfers with CCTP.**

  Bridge Kit is a lightweight SDK that uses CCTP as its protocol provider, letting
  you transfer USDC between blockchains in just a few lines of code.
</Tip>

## Key features

<CardGroup cols={3}>
  <Card title="Multichain asset transfers" icon="coins">
    Transfer USDC, EURC, and registered third-party assets across blockchains
    without traditional bridge liquidity pools
  </Card>

  <Card title="Configurable transfer speeds" icon="gauge-high">
    Choose between [Fast
    Transfer](/cctp/concepts/finality-and-block-confirmations#fast-transfer-attestation-times)
    for speed or [Standard
    Transfer](/cctp/concepts/finality-and-block-confirmations#standard-transfer-attestation-times)
    for cost efficiency
  </Card>

  <Card title="Programmable hooks" icon="code">
    Trigger automated actions on the destination blockchain after assets arrive
  </Card>
</CardGroup>

## What you can build

CCTP enables you to build applications that move digital assets across
blockchains. Here are some common use cases:

<AccordionGroup>
  <Accordion title="Crosschain liquidity management" icon="arrow-right-arrow-left">
    Rebalance digital asset holdings across blockchains to meet liquidity demands,
    manage treasury positions, or take advantage of market opportunities with
    minimal latency.
  </Accordion>

  <Accordion title="Crosschain swaps" icon="shuffle">
    Enable users to swap tokens on one blockchain for tokens on another blockchain
    by routing through USDC. Build seamless crosschain trading experiences that feel
    like a single transaction.
  </Accordion>

  <Accordion title="Crosschain payments" icon="credit-card">
    Accept USDC payments on one blockchain and automatically transfer funds to
    another blockchain where your business operations are based or where recipients
    prefer to receive funds.
  </Accordion>

  <Accordion title="Composable crosschain applications" icon="layer-group">
    Use CCTP hooks to chain together crosschain actions. Transfer assets across
    blockchains and automatically deposit them into DeFi protocols, purchase NFTs,
    or execute smart contract logic.
  </Accordion>
</AccordionGroup>

## Get started

<CardGroup cols={2}>
  <Card title="Transfer USDC from Ethereum to Arc" icon="rocket" href="/cctp/quickstarts/transfer-usdc-ethereum-to-arc">
    Build a script to transfer USDC between EVM blockchains using CCTP
  </Card>

  <Card title="Transfer USDC from Solana to Arc" icon="rocket" href="/cctp/quickstarts/transfer-usdc-solana-to-arc">
    Transfer USDC from Solana to an EVM blockchain using CCTP
  </Card>

  <Card title="Transfer USDC between Stellar and Arc" icon="rocket" href="/cctp/quickstarts/transfer-usdc-stellar-arc">
    Transfer USDC between Arc and Stellar using CCTP
  </Card>

  <Card title="Transfer USDC between Starknet and Arc" icon="rocket" href="/cctp/quickstarts/transfer-usdc-starknet-arc">
    Transfer USDC between Arc and Starknet using CCTP
  </Card>

  <Card title="Transfer USDC between Sui and Arc" icon="rocket" href="/cctp/quickstarts/transfer-usdc-sui-arc">
    Transfer USDC between Arc and Sui using CCTP
  </Card>
</CardGroup>

## CCTP for non-USDC assets

CCTP natively transfers USDC across blockchains using burn-and-mint. For EURC or
other registered ERC-20 assets, see
[CCTP for non-USDC assets](/cctp/expanded-assets), which extends CCTP's
attestation infrastructure to support EURC burn-and-mint and permissionless
wrapping of third-party assets (including pre-registered tokens like WETH).

| Feature | CCTP | CCTP for non-USDC |
| - | - | - |
| Token scope | USDC | EURC and any configured ERC-20 |
| Entry contract | `TokenMessengerV2` | `CrossChainTokenService` |
| Fee model | Fee deducted from the transferred amount | Fee paid in native gas on the source blockchain |
| Forwarding | Compulsory when used | Optional; requested at quote time |
| Attestation | Iris | Iris (shared with CCTP) |
| Hooks | Yes | Yes, with atomic on-arrival execution |
| Audiences | Anyone moving USDC or EURC | Token issuers, RWA platforms, and apps integrating third-party assets |

## Related products

CCTP and Gateway offer different approaches to crosschain transfers. This table
compares the two approaches.

| Attribute | CCTP | Gateway |
| - | - | - |
| **Use case** | Transfer USDC, EURC, or registered third-party assets from one blockchain to another | Hold a unified USDC balance accessible on any supported blockchain |
| **Transfer speed** | Fast Transfer: \~8-20 seconds<br />Standard Transfer: 15-19 minutes (Ethereum/L2s) | Instant (\<500 ms) after balance is established |
| **Balance model** | Point-to-point transfers | Unified crosschain balance |
| **Custody** | Non-custodial | Non-custodial with 7-day trustless withdrawal option |
| **Supported blockchains** | [View list](/cctp/concepts/supported-chains-and-domains) | [View list](/gateway/references/supported-blockchains) |