> ## 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.
# Release notes - CCTP - 2026
> 2026 release notes for CCTP
## October 2026
### Blockchain expansion
Added Sui mainnet and testnet as supported blockchains for CCTP (domain 8).
Updated topics:
* [Sui packages and interfaces](/cctp/references/sui-packages)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Transfer fees](/cctp/concepts/fees)
## September 2026
### Documentation additions
Added the following CCTP for non-USDC topic:
* [CCTP for non-USDC contract addresses](/cctp/expanded-assets/references/contract-addresses)
### Documentation additions
Added Starknet as a supported CCTP path to and from Arc.
* [Transfer USDC between Starknet and Arc](/cctp/quickstarts/transfer-usdc-starknet-arc)
* [CCTP Starknet contracts and interfaces](/cctp/references/starknet-contracts)
### Documentation additions
Launched **CCTP for non-USDC**. Token issuers and integrators can now register
their own tokens on the permissionless CCTP for non-USDC assets layer, in
addition to using pre-configured tokens like EURC.
* [CCTP for non-USDC assets overview](/cctp/expanded-assets)
* [Configure a custom token](/cctp/expanded-assets/quickstarts/configure-custom-token)
* [Deploy a native crosschain token](/cctp/expanded-assets/quickstarts/deploy-native-crosschain-token)
* [Configure an ownerless token](/cctp/expanded-assets/quickstarts/configure-ownerless-token)
* [Configure rate limits and caps](/cctp/expanded-assets/howtos/configure-rate-limits-and-caps)
* [Configure a denylist provider](/cctp/expanded-assets/howtos/configure-denylist-provider)
* [Denylist layers](/cctp/expanded-assets/concepts/denylist-layers)
### Blockchain expansion
Added Arc mainnet as a supported blockchain for CCTP.
Updated topics:
* [Contract addresses](/cctp/references/contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Transfer fees](/cctp/concepts/fees)
## August 2026
Added support for CCTP on Plasma mainnet and testnet (domain 33).
### Documentation updates
* [Contract Addresses](/cctp/references/contract-addresses)
* [Supported Blockchains and Domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and Block Confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Transfer Fees](/cctp/concepts/fees)
Added CCTP V2 support for Aptos (domain 9). You can now transfer USDC between
Aptos and any other CCTP V2 supported blockchain using standard transfers.
Previously, Aptos was available on CCTP V1 (Legacy) only.
### Documentation additions
* [Transfer USDC between Aptos and Arc](/cctp/quickstarts/transfer-usdc-aptos-arc)
* [Aptos packages and interfaces](/cctp/references/aptos-packages)
### Documentation updates
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Transfer fees](/cctp/concepts/fees)
* [Migrate from CCTP V1 (Legacy) to V2](/cctp/migration-from-v1-to-v2)
Added support for paying CCTP Fast Transfer and Forwarding Service fees upfront
on the source chain, in either native currency or USDC, through the new
`TokenMessengerWithFees` contract. Fees are collected at the source using a
signed, time-bound quote from the USDC Quote API, so the amount burned equals
the amount minted and recipients receive the full amount on the destination
chain.
### Documentation additions
* [Upfront fees for CCTP](/cctp/concepts/upfront-fees)
* [How upfront fees work](/cctp/concepts/how-upfront-fees-work)
* [Upfront fee quotes](/cctp/concepts/upfront-fee-quotes)
* [Transfer USDC with upfront fees](/cctp/howtos/transfer-usdc-with-upfront-fees)
* [Create USDC burn quote](/api-reference/cctp/all/create-usdc-burn-quote)
### Documentation updates
* [Contract interfaces](/cctp/references/contract-interfaces)
* [Contract addresses](/cctp/references/contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Transfer fees](/cctp/concepts/fees)
* [Forwarding Service](/cctp/concepts/forwarding-service)
Added support for X Layer (CCTP domain 37).
### Documentation updates
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Contract addresses](/cctp/references/contract-addresses)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Transfer fees](/cctp/concepts/fees)
## July 2026
Added support for gas-sponsored USDC deposits from Arbitrum to HyperCore through
the `CctpExtensionV2` contract. The extension uses EIP-3009 authorizations and a
relayer, so end users can deposit into HyperCore without holding ETH on
Arbitrum.
### Documentation additions
* [Transfer USDC from Arbitrum to HyperCore with CctpExtensionV2](/cctp/howtos/transfer-usdc-from-arbitrum-to-hypercore-with-cctp-extension-v2)
* [CctpExtensionV2 contract interface](/cctp/references/cctp-extension-v2-contract-interface)
* [HyperCore contract addresses](/cctp/references/hypercore-contract-addresses)
### Documentation updates
* [CCTP on HyperCore](/cctp/concepts/cctp-on-hypercore)
Added a new how-to for withdrawing USDC from HyperCore to Solana, including
base58 recipient encoding, Solana CCTP domain details, associated token account
(ATA) derivation, and `createATA` hook data examples.
### Documentation additions
* [Withdraw USDC from HyperCore to Solana](/cctp/howtos/withdraw-usdc-from-hypercore-to-solana)
### Documentation updates
* [Withdraw USDC from HyperCore to EVM chains](/cctp/howtos/withdraw-usdc-from-hypercore-to-evm)
## June 2026
Added support for Cronos mainnet.
### Documentation updates
Added the Cronos mainnet contract addresses:
* [Contract addresses](/cctp/references/contract-addresses)
Added support for Cronos testnet.
### Documentation updates
Updated the following topics to reflect Cronos support:
* [Contract addresses](/cctp/references/contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [CCTP fees](/cctp/concepts/fees)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
## May 2026
Added support for Stellar mainnet.
### Documentation additions
Added the following new topic to reflect Stellar mainnet support:
* [Transfer USDC on Stellar](/stablecoins/quickstart-transfer-usdc-stellar)
### Documentation updates
Updated the following topics to reflect Stellar mainnet support:
* [CCTP Stellar contracts and interfaces](/cctp/references/stellar-contracts)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
Added support for Injective mainnet.
### Documentation updates
Updated the following topics to reflect Injective mainnet support:
* [Contract Addresses: Mainnet](/cctp/references/contract-addresses#mainnet-contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
Updated Arc quickstarts to include a Forwarding Service branch.
### Documentation updates
Updated the following topics:
* [Transfer USDC from Ethereum to Arc](/cctp/quickstarts/transfer-usdc-ethereum-to-arc)
* [Transfer USDC from Solana to Arc](/cctp/quickstarts/transfer-usdc-solana-to-arc)
## April 2026
Added support for Pharos mainnet.
### Documentation updates
Updated the following topics to reflect Pharos mainnet support:
* [CCTP fees](/cctp/concepts/fees)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Contract Addresses: Mainnet](/cctp/references/contract-addresses#mainnet-contract-addresses)
Added support for Stellar testnet.
### Documentation additions
Added the following new topics to reflect Stellar testnet support:
* [CCTP on Stellar](/cctp/references/stellar)
* [CCTP Stellar contracts and interfaces](/cctp/references/stellar-contracts)
* [Transfer USDC between Stellar and Arc](/cctp/quickstarts/transfer-usdc-stellar-arc)
### Documentation updates
Updated the following topics to reflect Stellar testnet support:
* [Contract Addresses: Testnet](/cctp/references/contract-addresses#testnet-contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
## March 2026
Added support for Injective Testnet.
### Documentation updates
Updated the following topics to reflect Injective Testnet support:
* [Contract Addresses: Testnet](/cctp/references/contract-addresses#testnet-contract-addresses)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
Added support for Morph mainnet.
### Documentation updates
Updated the following topics to reflect Morph mainnet support:
* [Contract Addresses: Mainnet](/cctp/references/contract-addresses#mainnet-contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Technical Guide: Fees](/cctp/references/technical-guide#fees)
Added support for EDGE mainnet.
### Documentation updates
Updated the following topics to reflect EDGE mainnet support:
* [Contract Addresses: Mainnet](/cctp/references/contract-addresses#mainnet-contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Technical Guide: Fees](/cctp/references/technical-guide#fees)
## February 2026
Added support for Morph Hoodi Testnet.
### Documentation updates
Updated the following topics to reflect Morph Hoodi Testnet support:
* [Contract Addresses: Testnet](/cctp/references/contract-addresses#testnet-contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
Updated HyperCore CCTP transfer how-tos. Fixed signing parameters, contract
addresses, fee calculations, and modernized code examples.
### Documentation updates
Updated the following topics:
* [Withdraw USDC from HyperCore to EVM chains](/cctp/howtos/withdraw-usdc-from-hypercore-to-evm)
* [Withdraw USDC from HyperCore to HyperEVM](/cctp/howtos/withdraw-usdc-from-hypercore-to-hyperevm)
* [Transfer USDC from Ethereum to HyperCore](/cctp/howtos/transfer-usdc-from-ethereum-to-hypercore)
* [Transfer USDC from Solana to HyperCore](/cctp/howtos/transfer-usdc-from-solana-to-hypercore)
* [Transfer USDC from Arbitrum to HyperCore](/cctp/howtos/transfer-usdc-from-arbitrum-to-hypercore)
* [Transfer USDC from HyperEVM to HyperCore](/cctp/howtos/transfer-usdc-from-hyperevm-to-hypercore)
* [Transfer USDC with the Forwarding Service](/cctp/howtos/transfer-usdc-with-forwarding-service)
* [CCTP fees](/cctp/concepts/fees)
Added support for EDGE testnet.
### Documentation updates
Updated the following topics to reflect EDGE testnet support:
* [Contract addresses](/cctp/references/contract-addresses)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
## January 2026
Added support for the Circle Forwarding Service. The following new topics were
created:
### Documentation additions
* [Circle Forwarding Service](/cctp/concepts/forwarding-service)
* [Transfer USDC with the Forwarding Service](/cctp/howtos/transfer-usdc-with-forwarding-service)
### Documentation updates
* Updated the
[Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
topic to reflect the new Forwarding Service support.
### Documentation updates
Complete rewrite of the [CCTP documentation](/cctp) to focus on what you can
build with CCTP. Emphasized [Bridge Kit](https://docs.arc.io/app-kit/bridge) as
the easiest and preferred way to build with CCTP. Removed or reorganized
sections to make the documentation more focused and easier to navigate. Updated
the information architecture of the CCTP topics to be focused on the developer
experience. Added functional Solana examples.
The following topics were added or updated:
* [CCTP overview](/cctp)
* [Supported blockchains and domains](/cctp/concepts/supported-chains-and-domains)
* [Finality and block confirmations](/cctp/concepts/finality-and-block-confirmations)
* [Transfer USDC from Ethereum to Arc](/cctp/quickstarts/transfer-usdc-ethereum-to-arc)
* [Transfer USDC from Solana to Arc](/cctp/quickstarts/transfer-usdc-solana-to-arc)
* [Transfer fees](/cctp/concepts/fees)
* [Fast transfer allowance](/cctp/concepts/fast-transfer-allowance)
* [Get Transfer Fee](/cctp/howtos/get-transfer-fee)
* [Get Fast Transfer Allowance](/cctp/howtos/get-fast-transfer-allowance)
* [Troubleshoot Transfers](/cctp/howtos/troubleshoot-transfers)
* [Resolve Stuck Attestation](/cctp/howtos/resolve-stuck-attestation)
* [Retry Failed Mint](/cctp/howtos/retry-failed-mint)
* [Technical guide](/cctp/references/technical-guide)
* [Contract addresses](/cctp/references/contract-addresses)
* [Attestation verification](/cctp/references/attestation-verification)
* [Contract interfaces](/cctp/references/contract-interfaces)
* [Solana Programs](/cctp/references/solana-programs)
* [Starknet Contracts](/cctp/references/starknet-contracts)
Updated the [table of CCTP fees](/cctp/technical-guide#fees) to reflect the new
finality-indexed pricing model.