> ## 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. # Refund a payment intent ## OpenAPI ````yaml openapi/payments.yaml post /v1/paymentIntents/{id}/refund openapi: 3.0.2 info: version: ${version} title: Crypto Deposits API description: > The Circle Payments API allows you to take payments from your end users via traditional methods such as debit & credit cards and receive settlement in USDC. The Circle Payments API has been designed with any business or internet commerce in mind, not just crypto applications, and it's based on Circle's extensive experience processing millions of card payments since 2014. servers: - url: https://api-sandbox.circle.com - url: https://api.circle.com security: [] tags: - name: Payments description: Create, cancel, refund, and get updates on card payments. - name: Crypto Payment Intents description: Create and track intent for end user to pay via crypto. - name: Crypto Payment Customers description: >- Create and manage Travel Rule customers and customer wallets for crypto payment attribution. - name: Crypto Payment Refund Addresses description: Create refund address-book entries for crypto payment refunds. paths: /v1/paymentIntents/{id}/refund: post: tags: - Crypto Payment Intents summary: Refund a payment intent operationId: refundPaymentIntent parameters: - $ref: '#/components/parameters/IdPath' requestBody: content: application/json: schema: $ref: '#/components/schemas/CryptoRefundCreationRequest' responses: '201': description: Crypto refund successfully created for the given payment intent. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: title: CreateCryptoRefundResponse properties: data: $ref: '#/components/schemas/CryptoPayment' examples: response: value: data: id: 3389f4ba-aafd-4eef-aaa2-3292df8f62e6 type: refund status: pending amount: currency: USD merchantId: 5ffea093-d210-44b4-a7ca-ad33b9498188 merchantWalletId: '1000999922' paymentIntentId: 77c91fe9-e603-4e7b-9672-1ef8ac502cf6 settlementAmount: amount: '1.00' currency: ETH fromAddresses: chain: ETH addresses: - '0x0d4344cFF68F72A5B9Abded37CA5862941a62050' depositAddress: chain: ETH address: '0x97de855690955e0da79ce5c1b6804847e7070c7f' paymentId: 2e7b6557-1967-4348-ad81-daf3cee4c175 createDate: '2022-07-21T20:16:35.092852Z' updateDate: '2022-07-21T20:19:24.719313Z' failedRefund: value: data: id: 4489f4ba-aafd-4eef-aaa2-3292df8f62e7 type: refund status: failed errorCode: insufficient_funds amount: currency: USD merchantId: 5ffea093-d210-44b4-a7ca-ad33b9498188 merchantWalletId: '1000999922' paymentIntentId: 77c91fe9-e603-4e7b-9672-1ef8ac502cf6 settlementAmount: amount: '1.00' currency: ETH fromAddresses: chain: ETH addresses: - '0x0d4344cFF68F72A5B9Abded37CA5862941a62050' depositAddress: chain: ETH address: '0x97de855690955e0da79ce5c1b6804847e7070c7f' paymentId: 2e7b6557-1967-4348-ad81-daf3cee4c175 createDate: '2022-07-21T20:16:35.092852Z' updateDate: '2022-07-21T20:19:24.719313Z' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' '404': $ref: '#/components/responses/NotFound' security: - bearerAuth: [] components: parameters: IdPath: name: id description: Universally unique identifier (UUID v4) of a resource. in: path required: true schema: type: string format: uuid example: b3d9d2d5-4c12-4946-a09d-953e82fae2b0 schemas: CryptoRefundCreationRequest: type: object required: - idempotencyKey - destination - amount - toAmount properties: idempotencyKey: $ref: '#/components/schemas/IdempotencyKey' destination: $ref: '#/components/schemas/CryptoRefundDestination' amount: type: object description: >- The source amount of the refund, it can be in either the original payment currency or the settlement currency. required: - currency properties: currency: description: Currency code. type: string enum: - USD - ETH - BTC toAmount: type: object description: >- The destination amount of the refund, it must be in the original payment currency. required: - amount - currency properties: amount: description: Magnitude of the amount, in units of the currency, with a `.`. type: string example: '3.14' currency: description: Currency code. type: string enum: - USD - ETH - BTC paymentId: type: string format: uuid description: >- ID of the payment to attribute this refund to. Required for merchants registered under Circle's Singapore (`CIRCLE_SG`) or French (`CIRCLE_FR`) legal entity. example: 2e7b6557-1967-4348-ad81-daf3cee4c175 customerExternalRef: $ref: '#/components/schemas/PaymentCustomerExternalRef' description: >- Optional customer-supplied reference for this refund. Unlike payins, it is not inherited from the payment intent and is not part of the idempotency key, so a replay with the same idempotencyKey but a changed value returns the original refund. CryptoPayment: type: object description: Status information of the related payment. required: - id - type - merchantId - amount - status properties: id: $ref: '#/components/schemas/Id' type: type: string description: Type of the payment object. enum: - payment - refund merchantId: $ref: '#/components/schemas/IdMerchant' merchantWalletId: $ref: '#/components/schemas/MerchantWalletId' amount: $ref: '#/components/schemas/CryptoPaymentsOptionalAmountMoney' status: $ref: '#/components/schemas/PaymentStatus' statusReason: $ref: '#/components/schemas/CryptoPaymentStatusReason' errorCode: $ref: '#/components/schemas/CryptoPaymentErrorCode' nullable: true fees: $ref: '#/components/schemas/FiatMoneyUsd' networkFees: $ref: '#/components/schemas/CryptoPaymentNetworkFee' paymentIntentId: type: string format: uuid example: 6e4d4047-db14-4c09-b238-1215aee50d03 customerExternalRef: $ref: '#/components/schemas/PaymentCustomerExternalRef' description: A customer-supplied reference to reconcile transactions. settlementAmount: $ref: '#/components/schemas/FiatMoneyUsd' fromAddresses: type: object properties: chain: $ref: '#/components/schemas/Chain' addresses: type: array items: $ref: '#/components/schemas/Address' depositAddress: type: object properties: chain: $ref: '#/components/schemas/Chain' address: type: string example: '0x97de855690955e0da79ce5c1b6804847e7070c7f' addressTag: $ref: '#/components/schemas/AddressTag' transactionHash: type: string example: '0x7351585460bd657f320b9afa02a52c26d89272d0d10cc29913eb8b28e64fd906' refundIds: description: >- List of refunds associated with this payment. Only populated when `type` is `payment`. type: array items: type: string format: uuid example: 8edc0da8-d086-3051-a393-53f972d16444 paymentId: type: string format: uuid description: >- Identifier of the payment this refund is attributed to. Only populated when `type` is `refund` and the refund was attributed to a specific payment. example: 36a25933-8c2d-3c23-ad07-7fe1e41b5fe5 createDate: $ref: '#/components/schemas/UtcTimestamp' updateDate: $ref: '#/components/schemas/UtcTimestamp' riskEvaluation: $ref: '#/components/schemas/RiskEvaluation' 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 CryptoRefundDestination: type: object description: The destination of a crypto refund. properties: address: type: string description: >- The blockchain address. Required when `addressBookId` is not provided. example: '0x8381470ED67C3802402dbbFa0058E8871F017A6F' addressTag: $ref: '#/components/schemas/AddressTag' chain: description: >- The blockchain network. Required when `addressBookId` is not provided. allOf: - $ref: '#/components/schemas/Chain' addressBookId: type: string format: uuid description: >- Identifier of an existing Address Book entry to send the refund to. For merchants registered under Circle's Singapore legal entity, use this or `useOriginalSender`. example: e7f468c7-6a99-5639-b3ed-8c7d477abb47 useOriginalSender: type: boolean description: >- Set to `true` to refund to the original sender address of the attributed source payment. Available for merchants registered under Circle's Singapore legal entity. Can be used alongside `paymentId` on the refund request. example: true PaymentCustomerExternalRef: type: string format: uuid description: >- A customer-supplied reference for reconciliation purposes, used on payment intents, payments, and refunds. Must be a UUID. Payouts and transfers use a separate 21-character limit schema. example: 310c458a-18eb-4cbd-8a9a-586d9448ae69 Id: type: string description: Unique system generated identifier for the entity. format: uuid example: b8627ae8-732b-4d25-b947-1df8f4007a29 IdMerchant: type: string description: Unique system generated identifier for the merchant. format: uuid example: fc988ed5-c129-4f70-a064-e5beb7eb8e32 MerchantWalletId: type: string description: Unique system generated identifier for the wallet of the merchant. maxLength: 36 example: '212000' CryptoPaymentsOptionalAmountMoney: type: object required: - currency properties: amount: description: Magnitude of the amount, in units of the currency, with a `.`. type: string example: '3.14' currency: description: Currency code. type: string enum: - USD - ETH - BTC PaymentStatus: type: string description: >- Enumerated status of the payment. `pending` means the payment is waiting to be processed. `confirmed` means the payment has been approved by the bank and the merchant can treat it as successful, but settlement funds are not yet available to the merchant. `paid` means settlement funds have been received and are available to the merchant. `failed` means something went wrong (most commonly that the payment was denied). `action_required` means that additional steps are required to process this payment; refer to `requiredAction` for more details. Terminal states are `paid` and `failed`. enum: - pending - confirmed - paid - failed - action_required CryptoPaymentStatusReason: type: string description: > Provides additional context for certain payment statuses. | Status | Status Reason | Description | | --- | --- | --- | | `pending` | `compliance_review` | Compliance is awaiting PII before releasing funds. | | `failed` | `compliance_denied` | Funds seized due to sanctions hit. | | `failed` | `unsupported_wallet` | Funds are stuck in escrow because the sender wallet is not supported (self-hosted wallet or non-VASP). | | `paid` | `unsupported_wallet` | Funds have settled but were received from an unsupported VASP. | | `paid` or `pending` | `pii_not_received` | PII was not received within the Travel Rule window. | enum: - compliance_review - compliance_denied - unsupported_wallet - pii_not_received example: compliance_review CryptoPaymentErrorCode: type: string description: >- Indicates the failure reason of a crypto payment or refund. Only present when a failure reason is available (i.e. the underlying reason code is set). Possible values are `insufficient_funds`, `transaction_orphaned` and `payment_failed` nullable: true enum: - insufficient_funds - transaction_orphaned - payment_failed example: insufficient_funds FiatMoneyUsd: type: object required: - amount - currency properties: amount: description: Magnitude of the amount, in units of the currency, with a `.`. type: string example: '3.14' currency: description: Currency code. type: string enum: - USD CryptoPaymentNetworkFee: type: object required: - amount - currency properties: amount: description: Magnitude of the amount, in units of the currency, with a `.`. type: string example: '3.14' currency: type: string description: Currency code for the amount. enum: - USD - EUR - BTC - ETH feePayer: type: string description: The party that pays the network fee based on merchant configuration. enum: - endUser - merchant Chain: type: string description: A blockchain that a given currency is available on. enum: - ALGO - APTOS - ARB - ARC - AVAX - BASE - BTC - CELO - CODEX - ETH - HBAR - HYPEREVM - INK - LINEA - NEAR - NOBLE - OP - PLUME - PAH - PLASMA - POLY - SEI - SOL - SONIC - SUI - UNI - WORLDCHAIN - XLAYER - XDC - 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. **Important:** For Ripple (XRP) addresses, only the classic address format is supported (for example, `rPEPPER7kfTD9w2To4CQk6UCfuHM9c6GDY`). The `x-address` format is NOT supported currently (for example, `XV5sbjUmgPpvXv4ixFWZ5ptAYZ6PD2q1qM6owqNbug8W6KV`). example: '0x8381470ED67C3802402dbbFa0058E8871F017A6F' AddressTag: type: string 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. nullable: true example: '123456789' UtcTimestamp: type: string description: ISO-8601 UTC date/time format. example: '2020-04-10T02:13:30.000Z' RiskEvaluation: type: object description: >- Results of risk evaluation. Present when the payment's risk decision is `denied` or `review`. Absent when `decision` is `approved` or when no risk evaluation was performed. nullable: true properties: decision: description: Enumerated decision of the account. type: string enum: - approved - denied - review reason: description: >- Risk reason code for the decision. Known values include `3000` (transaction involves a sanctioned or unsupported wallet) and `2151` (transaction denied on outbound compliance screening; a failed refund, for example). Present when `decision` is `denied`; may be omitted for `review` decisions. type: string nullable: true example: '3000' 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. NotFound: description: The specified resource was not found. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: type: object title: NotFound required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 404 message: Not found. examples: response: value: code: 404 message: Not found. securitySchemes: bearerAuth: type: http scheme: bearer ````