> ## 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. # Request a settlement advance > Submit the Permit2 signature generated from the presign endpoint along with the witness payload. Funding runs asynchronously after this call returns. Idempotent on `tradeId`: replays for the same trade either return the in-progress settlement advance or short-circuit when the trade already has a non-failed active settlement advance. Calling `/reserve` first is optional. The request body is the same whether or not a prior reservation exists. **Collateral rounding**: when the repayment is complete and collateral is released, Circle rounds the collateral amount to 2 decimal places. ## OpenAPI ````yaml openapi/stablefx.yaml post /v1/exchange/stablefx/settlementAdvance openapi: 3.1.0 info: title: StableFX API description: > The StableFX API provides endpoints for trading stablecoins. ## Authentication All API requests require authentication using an API key. ## Base URL The base URL for all API endpoints is: `https://api.circle.com/v1/exchange/stablefx` version: 1.0.0 servers: - url: https://api.circle.com description: StableFX API server security: - BearerAuth: [] tags: - name: Quotes description: Endpoints for creating and managing quotes - name: Trades description: Endpoints for creating and managing trades - name: Signatures description: Endpoints for retrieving presign typed data and registering signatures - name: Fees description: Endpoints for retrieving fees - name: Funding description: Endpoints for funding trades - name: Webhook Subscriptions description: Manage subscriptions to notifications - name: Settlement Advance description: Request, track, and repay settlement advances. paths: /v1/exchange/stablefx/settlementAdvance: post: tags: - Settlement Advance summary: Request a settlement advance description: > Submit the Permit2 signature generated from the presign endpoint along with the witness payload. Funding runs asynchronously after this call returns. Idempotent on `tradeId`: replays for the same trade either return the in-progress settlement advance or short-circuit when the trade already has a non-failed active settlement advance. Calling `/reserve` first is optional. The request body is the same whether or not a prior reservation exists. **Collateral rounding**: when the repayment is complete and collateral is released, Circle rounds the collateral amount to 2 decimal places. operationId: requestSettlementAdvance requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AcceptSettlementAdvance' responses: '200': description: Settlement advance requested; funding in progress. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/SettlementAdvanceAccepted' '400': description: > Invalid request, signature mismatch, duplicate settlement advance, or credit limit exceeded. Relevant error codes: - `301031` (`INSUFFICIENT_CREDIT_LINE_FUNDS`) — the requested advance amount exceeds one of two limits enforced at creation time: 1. **USD headroom**: the USD-equivalent of the advance exceeds the credit line's remaining USD balance. 2. **Available-in-currency**: the advance amount (in the requested currency) exceeds the per-currency pool available for that stablecoin. Check the `availableInCurrencies` field on the credit line before requesting. content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: Trade or credit line not found. content: application/json: schema: $ref: '#/components/schemas/Error' '422': description: > The quoted exchange rate diverges from the live reference rate by more than the configured risk margin. Relevant error codes: - `301098` (`STABLE_FX_QUOTE_PRICE_DIVERGENCE`) — quote rate is outside the acceptable spread from the current TER fiat reference rate. Submit a fresh quote and retry. content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: > Settlement advance creation rate limit exceeded. The credit line has had too many advances created within the configured time window. Relevant error codes: - `301099` (`SETTLEMENT_ADVANCE_RATE_LIMITED`) — wait before retrying. content: application/json: schema: $ref: '#/components/schemas/Error' security: - BearerAuth: [] components: schemas: AcceptSettlementAdvance: type: object description: >- Request body for accepting a settlement advance by submitting a Permit2 signature. required: - idempotencyKey - tradeId - permit2 - signature properties: idempotencyKey: $ref: '#/components/schemas/IdempotencyKey' tradeId: type: string description: Trade identifier. example: trade-abc-123 permit2: $ref: '#/components/schemas/DelegateFundingPermit2' signature: type: string description: >- Maker's Permit2 signature over the typed data (0x-prefixed, 65 bytes hex). example: 0x6f5a...c1b9 SettlementAdvanceAccepted: type: object description: Settlement advance accepted; funding in progress. required: - advanceId - tradeId - status properties: advanceId: $ref: '#/components/schemas/Id' tradeId: $ref: '#/components/schemas/Id' status: $ref: '#/components/schemas/AdvanceCreditStatus' Error: title: Error type: object required: - code - message properties: code: $ref: '#/components/schemas/ErrorCode' message: type: string description: Human-readable message that describes the error. example: Unknown error occurred errors: type: array description: Array of detailed error descriptions items: $ref: '#/components/schemas/DescriptiveError' IdempotencyKey: type: string description: >- Universally unique identifier (UUID v4) idempotency key. This key is utilized to ensure exactly-once execution of mutating requests. To create a UUIDv4 go to [uuidgenerator.net](https://www.uuidgenerator.net). If the same key is reused, it will be treated as the same request and the original response will be returned. example: a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11 format: uuid DelegateFundingPermit2: type: object description: >- Permit2 PermitWitnessTransferFrom payload with DelegateFundingAuthorization witness. The `permitted.amount` is always 0 -- Permit2 is used as an authorization carrier, no tokens transfer from the trader. required: - permitted - spender - nonce - deadline - witness properties: permitted: $ref: '#/components/schemas/TokenPermissions' spender: type: string description: FxEscrow contract address. example: 0xFxEscrow000000000000000000000000000000000 nonce: type: string description: Permit2 nonce, as a string representation of a uint256. example: '1234567890' deadline: type: string description: >- Permit2 deadline (unix timestamp), as a string representation of a uint256. example: '1782556800' witness: $ref: '#/components/schemas/DelegateFundingAuthorization' XRequestId: type: string description: >- A unique identifier, which can be helpful for identifying a request when communicating with Circle support. example: 2adba88e-9d63-44bc-b975-9b6ae3440dde format: uuid Id: type: string format: uuid description: System-generated unique identifier of the resource. example: c4d1da72-111e-4d52-bdbf-2e74a2d803d5 AdvanceCreditStatus: type: string description: > Lifecycle status of the credit advanced against a settlement. - `funds_reserved` -- credit reserved on the line, awaiting maker action. - `requested` -- maker submitted the request; Circle is moving funds. - `disbursed` -- funds delivered to the funder passthrough wallet. - `past_due` -- repayment window has elapsed without full repayment. - `paid` -- credit fully repaid. - `rejected` -- credit line rejected the advance request. - `expired` -- reservation expired before being consumed. - `canceled` -- maker or Circle canceled the advance. enum: - funds_reserved - requested - disbursed - past_due - paid - rejected - expired - canceled example: disbursed ErrorCode: title: ErrorCode type: integer description: The code that corresponds to the error. enum: - -1 - 0 - 1 - 2 - 3 - 400 - 401 - 403 - 404 DescriptiveError: title: DescriptiveError type: object required: - error - message properties: error: $ref: '#/components/schemas/DescriptiveErrorType' location: type: - string - 'null' description: The key or path where the error occurred message: type: string description: Detailed description of the error TokenPermissions: type: object description: Token permissions for Permit2 required: - token - amount properties: token: type: string description: The token contract address example: 0xTOKEN amount: type: string description: >- The amount of tokens permitted, as a string representation of a uint256. example: '1000' DelegateFundingAuthorization: type: object description: >- DelegateFundingAuthorization witness binding the Permit2 authorization to a specific trade, funder, recipient, token, and amount. required: - id - funder - recipient - token - amount properties: id: type: string description: On-chain trade id (uint256). example: '987654321' funder: type: string description: >- Address of the funder wallet (Circle-controlled) authorized to deliver tokens on the trader's behalf. example: 0xLLCFunderPW...address recipient: type: string description: Address that receives the delivered tokens. example: 0xLLCEscrowPW...address token: type: string description: ERC-20 contract address of the token to be delivered. example: 0xMXNB...address amount: type: string description: >- Amount to be delivered by the funder, in token units (uint256, no decimals). Tokens use 6 decimal places, so 5000.00 MXNB is represented as "5000000000". example: '5000000000' DescriptiveErrorType: title: DescriptiveErrorType type: string enum: - MISSING_OR_INVALID_FIELD description: Type of descriptive error 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' securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: PREFIX:ID:SECRET description: >- Circle's API Keys are formatted in the following structure "PREFIX:ID:SECRET". All three parts are requred to make a successful request. ````