> ## 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 a mock Wire payment > In the sandbox environment, initiate a mock wire payment that mimics the behavior of funds sent through the bank (wire) account linked to master wallet. ## OpenAPI ````yaml openapi/account.yaml post /v1/mocks/payments/wire openapi: 3.0.2 info: version: ${version} title: Core Functionality description: > All of Circle's APIs share a common set of core functionality that lets you manage your Circle Account in a programmatic way. With a Circle Account your business can deposit traditional money from 80+ countries and seamlessly convert them into "digital currency dollars": USDC. You can then use USDC for everyday payments and treasury flows. servers: - url: https://api-sandbox.circle.com - url: https://api.circle.com security: [] tags: - name: Balances description: Get information on settled and unsettled balances. - name: Payouts description: Create and get information on 1st party payouts. - name: Wires description: >- Create, get instructions, and get information on 1st party bank accounts for wire transfers. - name: CUBIX description: Create and get information on CUBIX accounts. - name: PIX description: Create and get information on PIX accounts. - name: Transfers description: Create and get information on 1st party transfers. - name: Addresses description: Generate and get information on blockchain addresses. - name: Deposits description: Get information on 1st party deposits. - name: Payments description: Create, cancel, refund, and get updates on card payments. - name: Settlement Bank Routing description: View and manage settlement bank routing preferences for fiat accounts. - name: Reporting description: >- Retrieve transaction and balance reports, including ISO 20022 (CAMT.053) statements and managed-payment reports. paths: /v1/mocks/payments/wire: post: tags: - Payments summary: Create a mock Wire payment description: >- In the sandbox environment, initiate a mock wire payment that mimics the behavior of funds sent through the bank (wire) account linked to master wallet. operationId: createMockWirePayment requestBody: content: application/json: schema: $ref: '#/components/schemas/MockWirePaymentRequest' responses: '201': description: Successfully created a mock wire payment. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: title: CreateWirePaymentResponse properties: data: $ref: '#/components/schemas/MockWirePaymentResponse' examples: response: value: data: trackingRef: CIR13FB13A amount: amount: '3.14' currency: USD beneficiaryBank: accountNumber: '11111111' status: pending '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' security: - bearerAuth: [] components: schemas: MockWirePaymentRequest: type: object required: - trackingRef - amount - beneficiaryBank properties: trackingRef: type: string description: >- Wire tracking reference that needs to be set in the wire reference to beneficiary field. This field is retrievable through the response during wire creation or via the bank instruction endpoint. example: CIR13FB13A amount: $ref: '#/components/schemas/FiatMoneyUsd' beneficiaryBank: $ref: '#/components/schemas/MockWirePaymentBeneficiaryBankInstruction' memo: type: string description: Optional free-form text memo for client reference information. MockWirePaymentResponse: type: object properties: trackingRef: type: string description: >- Wire tracking reference that needs to be set in the wire reference to beneficiary field. This field is retrievable through the response during wire creation or via the bank instruction endpoint. example: CIR13FB13A amount: $ref: '#/components/schemas/FiatMoneyUsd' beneficiaryBank: $ref: '#/components/schemas/MockWirePaymentBeneficiaryBankInstruction' status: type: string description: >- Enumerated status of the wire payment. Status `pending` indicates that the wire payment is in process; `processed` indicates it finished successfully; `failed` indicates it failed. enum: - pending - processed - failed FiatMoneyUsd: type: object required: - amount - currency properties: amount: type: string description: Magnitude of the amount, in units of the currency, with a `.`. example: '3.14' currency: description: Currency code. type: string enum: - USD MockWirePaymentBeneficiaryBankInstruction: type: object required: - accountNumber properties: accountNumber: type: string description: >- Virtual account number or Circle corporate Wells Fargo wire account number that needs to be set as destination. example: '11111111' headers: XRequestId: description: >- Universally unique identifier (UUID v4) for the request. Helpful for identifying a request when communicating with Circle support. schema: type: string format: uuid example: 2adba88e-9d63-44bc-b975-9b6ae3440dde 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: type: object title: BadRequest required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 400 message: Bad request. examples: response: value: code: 400 message: Bad request. 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: type: object title: NotAuthorized required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 401 message: Malformed authorization. examples: response: value: code: 401 message: Malformed authorization. securitySchemes: bearerAuth: type: http scheme: bearer ````