> ## 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. # Create an address book recipient > Creates an address book recipient for crypto payouts. Use the returned `id` as `destination.id` when creating a payout. **Digital Asset Accounts:** the address book is available only for custody accounts (`purpose: custody`) and is for third-party payouts only. It is not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. Set `clientEntityId` to the end user who owns the custody account you will pay out from. A payout can only use a recipient created for that end user. ## OpenAPI ````yaml openapi/accounts.yaml post /v1/addressBook/recipients openapi: 3.1.0 info: version: 1.0.0 title: Accounts (Stablecoin) API description: > Circle's Accounts API provides endpoints for managing stablecoin accounts -- including transfers, withdrawals, deposits, wire and ACH bank accounts, and blockchain addresses. An **Account** is a general representation of a ledger or custody object that holds balances. It can be a business account, a stablecoin account ledger for an end user, an extra sub-ledger, or any future custody solution. license: name: Circle License url: https://circle.com/terms servers: - url: https://api-sandbox.circle.com - url: https://api.circle.com security: [] tags: - name: Accounts description: Manage accounts. - name: Account Groups description: Manage custody account groups and their memberships. - name: Limits description: View effective account limits and current usage. - name: Transfers description: Manage account transfers. - name: Transactions description: | Get a unified, customer-friendly view of account transaction activity. - name: Wires description: Manage account bank accounts for wire transfers. - name: Deposits description: Get information on account bank deposits. - name: Withdrawals description: Manage account bank withdrawals (fiat offramp). - name: ACH description: Manage account bank accounts for ACH transfers. - name: Deposit Addresses description: Manage account deposit addresses. - name: Recipient Addresses description: Manage account recipient addresses used for transfers. - name: Passkeys description: > Manage WebAuthn passkeys and Strong Customer Authentication (SCA) challenges for end users. - name: Crypto Payments description: > Get crypto payments and crypto refunds received through payment intents. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payments. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: Crypto Payment Intents description: > Create, expire, refund, and track payment intents for receiving crypto payments. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payments. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: Crypto Payouts description: > Create and track crypto payouts to recipient addresses. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payouts. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: Crypto Address Book description: > Manage address book recipients used as crypto payout destinations. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payouts. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: Webhook Subscriptions description: Manage subscriptions to Digital Asset Accounts webhook notifications. paths: /v1/addressBook/recipients: post: tags: - Crypto Address Book summary: Create an address book recipient description: > Creates an address book recipient for crypto payouts. Use the returned `id` as `destination.id` when creating a payout. **Digital Asset Accounts:** the address book is available only for custody accounts (`purpose: custody`) and is for third-party payouts only. It is not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. Set `clientEntityId` to the end user who owns the custody account you will pay out from. A payout can only use a recipient created for that end user. operationId: createAddressBookRecipient requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AddressBookRecipientCreationRequest' responses: '201': description: Successfully created an address book recipient. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/CreateAddressBookRecipientResponse' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' '404': $ref: '#/components/responses/NotFound' '409': $ref: '#/components/responses/Conflict' '500': $ref: '#/components/responses/InternalServerError' security: - bearerAuth: [] components: schemas: AddressBookRecipientCreationRequest: type: object required: - clientEntityId - idempotencyKey - chain - address - metadata properties: clientEntityId: type: string format: uuid description: > Identifier of the end user's client entity this recipient is for. Required for Digital Asset Accounts: a payout can only use a recipient created for the end user that owns the payout's source account. example: a3f1b2c4-d5e6-7890-abcd-ef1234567890 idempotencyKey: $ref: '#/components/schemas/IdempotencyKey' chain: $ref: '#/components/schemas/AddressBookRecipientChain' address: $ref: '#/components/schemas/Address' addressTag: $ref: '#/components/schemas/AddressTag' metadata: $ref: '#/components/schemas/AddressBookRecipientMetadata' CreateAddressBookRecipientResponse: title: CreateAddressBookRecipientResponse properties: data: $ref: '#/components/schemas/AddressBookRecipient' IdempotencyKey: type: string description: >- Universally unique identifier (UUID v4) idempotency key. This key is utilized to ensure exactly-once execution of mutating requests. format: uuid example: ba943ff1-ca16-49b2-ba55-1057e70ca5c7 AddressBookRecipientChain: type: string description: Blockchain network code for the recipient address (address book scope). enum: - ALGO - APTOS - ARB - AVAX - BASE - CELO - ETH - HBAR - NEAR - NOBLE - OP - PAH - POLY - SOL - SUI - UNI - XLM - XRP - ZKS Address: type: string description: > An alphanumeric string representing a blockchain address. Formatting varies by blockchain. Be sure to preserve the exact formatting and capitalization of the address. example: '0x8381470ED67C3802402dbbFa0058E8871F017A6F' AddressTag: type: - string - 'null' description: >- The secondary identifier for a blockchain address. An example of this is the memo field on the Stellar network, which can be text, ID, or hash format. example: '123456789' AddressBookRecipientMetadata: type: object description: Recipient metadata. properties: nickname: type: string description: Nickname related to the address. example: sample nickname email: type: string description: Email address of the recipient. maxLength: 1024 example: satoshi@circle.com bns: type: string description: Blockchain Name Service (for example, ENS) domain for the address. example: sample.circle XRequestId: type: string format: uuid example: 2adba88e-9d63-44bc-b975-9b6ae3440dde AddressBookRecipient: type: object description: > An address book recipient. Use its `id` as `destination.id` when creating a crypto payout. properties: id: $ref: '#/components/schemas/Id' accountId: type: integer description: The account number the recipient is attached to. example: 1000662322 clientEntityId: type: string format: uuid description: >- Identifier of the end user's client entity, when the recipient was created for an end user. example: a3f1b2c4-d5e6-7890-abcd-ef1234567890 chain: $ref: '#/components/schemas/Chain' address: $ref: '#/components/schemas/Address' addressTag: $ref: '#/components/schemas/AddressTag' metadata: $ref: '#/components/schemas/AddressBookRecipientMetadata' status: $ref: '#/components/schemas/AddressBookRecipientStatus' riskEvaluation: $ref: '#/components/schemas/RiskEvaluation' createDate: $ref: '#/components/schemas/UtcTimestamp' updateDate: $ref: '#/components/schemas/UtcTimestamp' Error: type: object required: - code - message properties: code: type: integer description: > Circle internal status code from the platform `CoreStatusCode` enum (and its domain-specific extensions). **This is not the HTTP status code** — `-1` is the catch-all unknown error, `1`/`2` indicate API parameter problems, `3` is forbidden, `4` is unauthorized, and larger values identify domain-specific failures. Consumers should rely on the HTTP status line for transport-level error class and on this field for the specific Circle error case. example: 2 message: type: string description: >- Internal error message; suitable for logging but not for end-user display. example: API parameter invalid. externalMessage: type: string description: > End-user-displayable error message. Present when the server has generated a customer-facing variant for this error; omitted otherwise. example: The provided amount exceeds the maximum allowed. errors: type: array description: Additional request-field validation errors, when available. items: $ref: '#/components/schemas/ErrorDetail' Id: type: string description: Unique system-generated identifier for the entity. format: uuid example: b8627ae8-732b-4d25-b947-1df8f4007a29 Chain: type: string description: A blockchain that a given currency is available on. example: ETH enum: - ALGO - APTOS - ARB - ARC - AVAX - BASE - BTC - CELO - CODEX - ETH - HBAR - HYPEREVM - INK - LINEA - NEAR - NOBLE - OP - PLUME - PAH - POLY - SEI - SOL - SONIC - SUI - UNI - WORLDCHAIN - XDC - XLM - XRP - ZKS AddressBookRecipientStatus: type: string description: > Status of the address book recipient. Payouts require `active`. `pending` means the recipient is under risk review, and `inactive` means it is in a waiting period before it can receive payouts. enum: - pending - pending_verification - pending_additional_information - pending_owner_information - pending_beneficiary_information - denied - inactive - verification_succeeded - active - on_hold - failed - disabled RiskEvaluation: type: - object - 'null' description: >- Results of risk evaluation. Only present if the payment is denied by Circle's risk service. properties: decision: description: Enumerated decision of the account. type: string enum: - approved - denied - review reason: description: Risk reason for the definitive decision outcome. type: - string - 'null' example: '3000' UtcTimestamp: type: string description: ISO-8601 UTC date/time format. example: '2020-04-10T02:13:30.000Z' ErrorDetail: type: object required: - error - message properties: error: type: string description: Machine-readable error identifier. example: invalid_value location: type: string description: Query parameter or request field that caused the error. example: assetType message: type: string description: Human-readable description of the specific error. example: The operation and assetType combination is invalid. headers: XRequestId: description: > Circle-generated universally unique identifier (UUID v4). Useful for identifying a specific request when communicating with Circle Support. schema: $ref: '#/components/schemas/XRequestId' responses: BadRequest: description: The request cannot be processed due to a client error. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: 2 message: API parameter invalid. NotAuthorized: description: >- The request has not been applied because it lacks valid authentication credentials. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: 4 message: Unauthorized. NotFound: description: The specified resource was not found. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: 404 message: Not found. Conflict: description: The request conflicts with an existing resource or idempotent request. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: 409 message: Conflict. InternalServerError: description: >- The server encountered an unexpected condition that prevented it from fulfilling the request. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: -1 message: 'Something went wrong. errId: 1f0b0c455e40f753f07b4f0ae6abd4b4' securitySchemes: bearerAuth: type: http scheme: bearer ````