> ## 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 - Circle Payments Network - 2026 > 2026 release notes for Circle Payments Network ## September 2026 ### API updates **Managed Payments webhooks have moved to v2.** Update your webhook endpoints, signature verification, and event handlers to the v2 envelope and payloads. * [Managed Payments webhooks](/api-reference/cpn/managed-payments/webhooks/custody-transfer) * [Webhooks](/api-reference/webhooks) * [Set up a webhook endpoint](/api-reference/webhook-endpoints) ### Blockchain expansion Added Arc mainnet as a supported CPN settlement chain. Arc supports Transactions V2 only. Updated topics: * [Supported blockchains](/cpn/references/blockchains/supported-blockchains) * [Payment smart contract addresses](/cpn/references/blockchains/contract-addresses) * [Wallet provider compatibility](/cpn/references/blockchains/wallet-provider-compatibility) * [How-to: Grant USDC allowance to Permit2](/cpn/guides/transactions/grant-usdc-allowance-to-permit2) * [How-to: Migrate from transactions V1 to V2](/cpn/guides/transactions/migrate-from-txn-v1-to-v2) ### Error code additions * `290349 BLOCKCHAIN_UNSUPPORTED_FOR_V1`: returned when a quote or transaction is requested with `transactionVersion=VERSION_1` on a chain that supports Transactions V2 only (for example, Arc). ## August 2026 ### New features Managed Payments now supports internal account transfers, letting you move USDC balances between a main account and its subaccounts (or between two subaccounts under the same parent) in a single API call. Transfers are restricted to accounts you own; third-party address book recipients and cross-parent transfers are rejected. Access is included in the existing `MANAGED_PAYMENTS_PAYIN_ROLE` and `MANAGED_PAYMENTS_PAYOUT_ROLE` permissions — no additional entitlement is required. ### API updates Added the following endpoints: * [`POST /v1/accounts/transfers`](/api-reference/cpn/managed-payments/transfers/create-account-transfer) * [`GET /v1/accounts/transfers`](/api-reference/cpn/managed-payments/transfers/list-account-transfers) * [`GET /v1/accounts/transfers/{id}`](/api-reference/cpn/managed-payments/transfers/get-account-transfer) ## July 2026 ### API updates Managed Payments withdrawals now support a **burn-all** option that withdraws the full balance across the main wallet and all sub-accounts in a single operation. * Added a `burnAll` boolean field on [`POST /v1/cpn/managedPayments/accounts/{accountId}/withdrawals`](/api-reference/cpn/managed-payments/withdrawals/create-account-withdrawal). Set to `true` to sweep every sub-account together with the main wallet. * Withdrawal responses now include `burnAll` and a `subAccountSweeps` array that reports the amount and status (`pending`, `complete`, `failed`, `skipped`) for each sub-account sweep. See [`GET /v1/cpn/managedPayments/accounts/{accountId}/withdrawals/{withdrawalId}`](/api-reference/cpn/managed-payments/withdrawals/get-account-withdrawal). ### API updates CPN Gateway now validates IBAN account numbers submitted by Originating Financial Institutions (OFIs). Submissions with invalid structure, incorrect check digits, unsupported country codes, or IBAN country codes that don't match the associated `BANK_COUNTRY` are rejected before routing. Review the new reference so you can validate on your side before submission: * [Validating IBAN account numbers](/cpn/references/compliance/validating-iban) ## April 2026 ### Documentation additions Added the following new topic for Managed Payments webhook events: * [Webhook events](/api-reference/cpn/managed-payments/webhooks/custody-transfer) ### API updates Added and corrected the following Managed Payments endpoints: * [`GET /v1/cpn/managedPayments/accounts/{accountId}/deposits`](/api-reference/cpn/managed-payments/deposits/list-account-deposits) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/deposits/{depositId}`](/api-reference/cpn/managed-payments/deposits/get-account-deposit) * [`POST /v1/cpn/managedPayments/accounts/{accountId}/wireAccounts`](/api-reference/cpn/managed-payments/wires/create-account-wire-account) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/wireAccounts/{wireAccountId}/instructions`](/api-reference/cpn/managed-payments/wires/get-account-wire-account-instructions) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/wireAccounts/{wireAccountId}`](/api-reference/cpn/managed-payments/wires/get-account-wire-account) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/wireAccounts`](/api-reference/cpn/managed-payments/wires/list-account-wire-accounts) * [`POST /v1/cpn/managedPayments/accounts/{accountId}/withdrawals`](/api-reference/cpn/managed-payments/withdrawals/create-account-withdrawal) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/withdrawals`](/api-reference/cpn/managed-payments/withdrawals/list-account-withdrawals) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/withdrawals/{withdrawalId}`](/api-reference/cpn/managed-payments/withdrawals/get-account-withdrawal) ### API additions Added the following Managed Payments credit endpoints: * [`POST /v1/cpn/managedPayments/credit/transfers`](/api-reference/cpn/managed-payments/credit/create-managed-payments-credit-transfer) * [`GET /v1/cpn/managedPayments/credit/line`](/api-reference/cpn/managed-payments/credit/get-managed-payments-credit-line) * [`GET /v1/cpn/managedPayments/credit/transfers/{transferId}`](/api-reference/cpn/managed-payments/credit/get-managed-payments-credit-transfer) * [`GET /v1/cpn/managedPayments/credit/wireInstructions`](/api-reference/cpn/managed-payments/credit/get-managed-payments-credit-wire-instructions) * [`GET /v1/cpn/managedPayments/credit/transfers`](/api-reference/cpn/managed-payments/credit/list-managed-payments-credit-transfers) Added documentation for CPN Managed Payments. With Managed Payments, Circle handles licensing, compliance, minting, and settlement so you can offer stablecoin payments without building these systems yourself. ### Documentation additions Added the following topics for Managed Payments: * [CPN Managed Payments Overview](/cpn/managed-payments) * [Quickstart: Receive stablecoin payins](/cpn/managed-payments/quickstarts/receive-stablecoin-payins) * [Quickstart: Send stablecoin payouts](/cpn/managed-payments/quickstarts/send-stablecoin-payouts) * [Settlement flows](/cpn/managed-payments/concepts/settlement-flows) * [Sub-account architecture](/cpn/managed-payments/concepts/sub-account-architecture) ### API additions Added the following Managed Payments endpoints: * [`GET /v1/cpn/managedPayments/accounts`](/api-reference/cpn/managed-payments/accounts/list-accounts) * [`POST /v1/cpn/managedPayments/accounts`](/api-reference/cpn/managed-payments/accounts/create-account) * [`GET /v1/cpn/managedPayments/accounts/{accountId}`](/api-reference/cpn/managed-payments/accounts/get-account) * [`GET /v1/cpn/managedPayments/paymentIntents`](/api-reference/cpn/managed-payments/payment-intents/list-payment-intents) * [`POST /v1/cpn/managedPayments/paymentIntents`](/api-reference/cpn/managed-payments/payment-intents/create-payment-intent) * [`GET /v1/cpn/managedPayments/paymentIntents/{paymentIntentId}`](/api-reference/cpn/managed-payments/payment-intents/get-payment-intent) * [`POST /v1/cpn/managedPayments/paymentIntents/{paymentIntentId}/expire`](/api-reference/cpn/managed-payments/payment-intents/expire-payment-intent) * [`POST /v1/cpn/managedPayments/paymentIntents/{paymentIntentId}/refund`](/api-reference/cpn/managed-payments/payment-intents/refund-payment-intent) * [`GET /v1/cpn/managedPayments/payments`](/api-reference/cpn/managed-payments/payments/list-payments) * [`GET /v1/cpn/managedPayments/payments/{paymentId}`](/api-reference/cpn/managed-payments/payments/get-payment) * [`POST /v1/cpn/managedPayments/accounts/{accountId}/withdrawals`](/api-reference/cpn/managed-payments/withdrawals/create-account-withdrawal) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/withdrawals`](/api-reference/cpn/managed-payments/withdrawals/list-account-withdrawals) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/withdrawals/{withdrawalId}`](/api-reference/cpn/managed-payments/withdrawals/get-account-withdrawal) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/deposits`](/api-reference/cpn/managed-payments/deposits/list-account-deposits) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/deposits/{depositId}`](/api-reference/cpn/managed-payments/deposits/get-account-deposit) * [`POST /v1/cpn/managedPayments/accounts/{accountId}/wireAccounts`](/api-reference/cpn/managed-payments/wires/create-account-wire-account) * [`GET /v1/cpn/managedPayments/accounts/{accountId}/wireAccounts/{wireAccountId}/instructions`](/api-reference/cpn/managed-payments/wires/get-account-wire-account-instructions) * [`GET /v1/cpn/managedPayments/addressBook/recipients`](/api-reference/cpn/managed-payments/address-book/list-address-book-recipients) * [`POST /v1/cpn/managedPayments/addressBook/recipients`](/api-reference/cpn/managed-payments/address-book/create-address-book-recipient) * [`GET /v1/cpn/managedPayments/addressBook/recipients/{recipientId}`](/api-reference/cpn/managed-payments/address-book/get-address-book-recipient) * [`PATCH /v1/cpn/managedPayments/addressBook/recipients/{recipientId}`](/api-reference/cpn/managed-payments/address-book/modify-address-book-recipient) * [`DELETE /v1/cpn/managedPayments/addressBook/recipients/{recipientId}`](/api-reference/cpn/managed-payments/address-book/delete-address-book-recipient) * [`GET /v1/cpn/managedPayments/payouts`](/api-reference/cpn/managed-payments/payouts/list-payouts) * [`POST /v1/cpn/managedPayments/payouts`](/api-reference/cpn/managed-payments/payouts/create-payout) * [`GET /v1/cpn/managedPayments/payouts/{payoutId}`](/api-reference/cpn/managed-payments/payouts/get-payout) Documentation updates for **CPN Console 2.0**: expanded and clarified developer docs for Circle Payments Network (CPN), including new how-tos, navigation updates, a refreshed landing page, webhook guidance, and quickstart improvements. ### Documentation additions * [How-to: Set up a Circle wallet for CPN payments](/cpn/guides/wallets/setup-circle-wallet-for-cpn-payments) * [How-to: Set up Circle on/off-ramps for CPN payments](/cpn/guides/circle-liquidity/setup-circle-on-off-ramps-for-cpn-payments) * [Bring your own wallet for CPN](/cpn/concepts/wallets/bring-your-own-wallet) ### Documentation updates * [CPN overview](/cpn) * [Quickstart: Integrate with CPN as an OFI](/cpn/quickstarts/integrate-with-cpn-ofi) * [Webhook events](/cpn/references/webhooks/webhook-events)