> ## 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. # Initiate a crypto repayment > Initiates a crypto repayment for a credit transfer. The requested amount is capped at the outstanding balance. If the minimum of the requested amount and outstanding balance is zero, the request will be rejected with HTTP 400. **Note:** This endpoint is only available for Line of Credit products. Crypto repayment is not supported for Settlement Advance products. ## OpenAPI ````yaml openapi/credit.yaml post /v1/credit/cryptoRepayment openapi: 3.0.2 info: version: ${version} title: Credit API description: > The Circle Credit API provides access to credit facilities including Line of Credit and Settlement Advance products. **Line of Credit** enables direct drawdowns with auto-approval and asynchronous disbursement. Supports both fiat and crypto repayment. **Settlement Advance** requires a reserve-then-request flow with manual approval. Requires wire proof upload for disbursement approval. Supports fiat repayment only. servers: - url: https://api-sandbox.circle.com - url: https://api.circle.com security: [] tags: - name: Credit description: Get credit line details. - name: Credit Transfers description: Create, reserve, and manage credit transfers (drawdowns). - name: Credit Fees description: View fees charged on credit transfers. - name: Credit Repayments description: View and initiate repayments on credit transfers. paths: /v1/credit/cryptoRepayment: post: tags: - Credit Repayments summary: Initiate a crypto repayment description: > Initiates a crypto repayment for a credit transfer. The requested amount is capped at the outstanding balance. If the minimum of the requested amount and outstanding balance is zero, the request will be rejected with HTTP 400. **Note:** This endpoint is only available for Line of Credit products. Crypto repayment is not supported for Settlement Advance products. operationId: createCreditCryptoRepayment requestBody: content: application/json: schema: $ref: '#/components/schemas/CreditCryptoRepaymentCreationRequest' example: idempotencyKey: ba943ff1-ca16-49b2-ba55-1057e70ca5c7 amount: amount: '25000.00' currency: USD responses: '201': description: Successfully initiated a crypto repayment. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: title: CreateCreditCryptoRepaymentResponse properties: data: $ref: '#/components/schemas/CreditCryptoRepayment' example: data: id: e5f6a7b8-9012-3456-efab-345678901234 amount: amount: '25000.00' currency: USD status: pending createDate: '2024-03-25T10:00:00.000Z' updateDate: '2024-03-25T10:00:00.000Z' accountId: '1000000' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' '409': $ref: '#/components/responses/Conflict' security: - bearerAuth: [] components: schemas: CreditCryptoRepaymentCreationRequest: type: object description: Request body for initiating a crypto repayment on a credit transfer. required: - idempotencyKey - amount properties: idempotencyKey: $ref: '#/components/schemas/IdempotencyKey' amount: $ref: '#/components/schemas/FiatMoneyUsd' description: >- The amount and currency to repay. Currency must match the credit line currency. The requested amount is capped at the outstanding balance. accountId: description: >- Optional identifier of the funding account for the repayment. When omitted, falls back to the entity's default funding account. type: string example: '1000000' CreditCryptoRepayment: type: object description: A crypto repayment initiated on a credit transfer. required: - id - amount - status - createDate - updateDate properties: id: description: Unique identifier of the crypto repayment. type: string format: uuid example: b3d9d2d5-4c12-4946-a09d-953e82fae2b0 amount: $ref: '#/components/schemas/FiatMoneyUsd' description: The repayment amount. status: description: Current status of the crypto repayment. type: string enum: - pending example: pending createDate: $ref: '#/components/schemas/UtcTimestamp' description: ISO-8601 UTC date/time when the crypto repayment was created. updateDate: $ref: '#/components/schemas/UtcTimestamp' description: ISO-8601 UTC date/time when the crypto repayment was last updated. accountId: description: Unique identifier of the account the funds moved through. type: string example: '1000000' 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 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 UtcTimestamp: type: string description: ISO-8601 UTC date/time format. example: '2020-04-10T02:13:30.000Z' 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. Conflict: description: >- The request has not been applied because it comes in conflict with another request (such as re-using an idempotencyKey for a different request). headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: type: object title: Conflict required: - code - message properties: code: type: integer example: 400 message: type: string example: Something went wrong. example: code: 409 message: Conflicts with another request. examples: response: value: code: 409 message: Conflicts with another request. securitySchemes: bearerAuth: type: http scheme: bearer ````