> ## Documentation Index > Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt > Use this file to discover all available pages before exploring further. # Create a refund > Opens a MED 2.0 refund for a contested transaction. If an OPEN refund already exists for the same transaction, organization, and requesting participant, a sequential retry returns the existing refund with HTTP 200. Idempotency-Key is required and deduplicates retries, including concurrent requests. The transaction amount is validated against the SPI; a successful creation returns HTTP 201 with status OPEN. The requesting participant is determined by the authenticated tenant. participant, requestingParticipant, contestedParticipant, and organizationId are rejected when included in the body. ## OpenAPI ````yaml /es/openapi/v3-current/pix-lerian-dict.yaml post /dict/refunds openapi: 3.1.0 info: contact: name: Lerian Studio url: https://lerian.studio description: >- Public API for Pix keys, claims, fraud markers, infraction reports, and MED funds recovery. This release provides a mock-provider integration for testing; live BACEN connectivity is not included. license: name: Lerian Studio General License title: Pix Lerian — DICT version: 1.0.0 servers: - url: https://api.example.com/dict-hub/v1 description: >- Replace the example host with the URL provided during environment onboarding. security: - BearerAuth: [] tags: - description: Manage ownership and portability claims for Pix keys. name: Claims - description: Register, retrieve, list, update, and remove Pix keys. name: Entries - description: Create, query, list, and cancel DICT fraud markers. name: Fraud Markers - description: Manage participant-scoped MED 2.0 funds recoveries. name: Funds Recoveries - description: Manage MED 2.0 infraction reports for the authenticated organization. name: Infraction Reports - description: Look up Pix keys and check whether keys exist in the DICT directory. name: Keys - description: Create, query, cancel, and settle MED 2.0 refunds. name: Refunds paths: /dict/refunds: post: tags: - Refunds summary: Create a refund description: >- Opens a MED 2.0 refund for a contested transaction. If an OPEN refund already exists for the same transaction, organization, and requesting participant, a sequential retry returns the existing refund with HTTP 200. Idempotency-Key is required and deduplicates retries, including concurrent requests. The transaction amount is validated against the SPI; a successful creation returns HTTP 201 with status OPEN. The requesting participant is determined by the authenticated tenant. participant, requestingParticipant, contestedParticipant, and organizationId are rejected when included in the body. operationId: createRefund parameters: - description: >- REQUIRED. Client-supplied replay key, at most 64 bytes. A request without it is refused with PIX-0030 @ 400 before the handler runs. Replaying the same key with a divergent method, URL or body is PIX-0031 @ 412. in: header name: X-Idempotency required: true schema: maxLength: 64 minLength: 1 type: string - description: >- Best-effort business correlation id (observability only; never fabricated). in: header name: X-Correlation-Id schema: description: >- Best-effort business correlation id (observability only; never fabricated). type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/CreateRefundBody' required: true responses: '201': content: application/json: schema: $ref: '#/components/schemas/RefundView' description: Created '400': content: application/json: example: code: PIX-0030 title: Idempotency Key Required message: >- The Idempotency-Key header is required for this operation and must be within the accepted length. schema: $ref: '#/components/schemas/LegacyErrorEnvelope' application/problem+json: example: type: https://errors.lerian.studio/v1/PIX-0001 title: Bad Request status: 400 detail: Your request is missing one or more required header params. code: PIX-0001 schema: $ref: '#/components/schemas/Detail' description: >- Bad Request (PIX-0001, PIX-0002, PIX-0003, PIX-0017, PIX-0015, PIX-0020). X-Idempotency absent or longer than 64 bytes (PIX-0030). Legacy {code,title,message} envelope, NOT problem+json. '403': content: application/problem+json: example: type: https://errors.lerian.studio/v1/PIX-0005 title: Forbidden status: 403 detail: You do not have permission to perform this operation. code: PIX-0005 schema: $ref: '#/components/schemas/Detail' description: Forbidden (PIX-0005). '404': content: application/problem+json: example: type: https://errors.lerian.studio/v1/PIX-0011 title: Not Found status: 404 detail: >- No entity was found for the given ID. Please make sure to use the correct ID. code: PIX-0011 schema: $ref: '#/components/schemas/Detail' description: Not Found (PIX-0011). '409': content: application/problem+json: example: type: https://errors.lerian.studio/v1/PIX-0012 title: Conflict status: 409 detail: >- The entity already exists or conflicts with an existing resource. code: PIX-0012 schema: $ref: '#/components/schemas/Detail' description: Conflict (PIX-0012, PIX-0033). '412': content: application/json: example: code: PIX-0031 title: Idempotency Key Conflict message: The Idempotency-Key was already used with a different request. schema: $ref: '#/components/schemas/LegacyErrorEnvelope' description: >- X-Idempotency replayed with a divergent request -- a different method, URL (including the path parameter), body, or identity header among X-Account-Id / X-Reason / X-End-To-End-Id (PIX-0031). Legacy {code,title,message} envelope, NOT problem+json. '422': content: application/problem+json: example: type: https://errors.lerian.studio/v1/PIX-0013 title: Unprocessable Entity status: 422 detail: >- The operation could not be processed due to a business rule violation. code: PIX-0013 schema: $ref: '#/components/schemas/Detail' description: Unprocessable Entity (PIX-0013). '500': content: application/problem+json: example: type: https://errors.lerian.studio/v1/PIX-0000 title: Internal Server Error status: 500 detail: internal error code: PIX-0000 schema: $ref: '#/components/schemas/Detail' description: Internal Server Error (PIX-0000). '502': content: application/problem+json: example: type: https://errors.lerian.studio/v1/PIX-0141 title: Bad Gateway status: 502 detail: internal error code: PIX-0141 schema: $ref: '#/components/schemas/Detail' description: Bad Gateway (PIX-0141). '503': content: application/json: example: code: PIX-0032 title: Idempotency Unavailable message: >- The request was not processed because the idempotency store is unavailable. Please retry. schema: $ref: '#/components/schemas/LegacyErrorEnvelope' description: >- Replay cache unavailable on this fail-closed route, so the mutation was refused rather than executed without replay protection (PIX-0032). Legacy {code,title,message} envelope, NOT problem+json. default: content: application/problem+json: schema: $ref: '#/components/schemas/Detail' description: Error components: schemas: CreateRefundBody: additionalProperties: false properties: refundAmount: examples: - '1000.00' type: string refundDetails: examples: - refund due to operational failure type: string refundReason: enum: - FRAUD - OPERATIONAL_FLAW - PIX_AUTOMATICO - REFUND_CANCELLED examples: - OPERATIONAL_FLAW type: string transactionId: examples: - E12345678202601011200abcdef01234 type: string required: - transactionId - refundReason - refundAmount type: object RefundView: additionalProperties: false properties: alreadySettledAmount: type: string analysisDetails: type: string analysisResult: enum: - TOTALLY_ACCEPTED - PARTIALLY_ACCEPTED - REJECTED type: string bacenRefundId: examples: - 3d48532f-1a2b-4422-81c3-b7dc852e262b type: string contestedParticipant: examples: - '87654321' type: string correlationId: examples: - 9f3a8b7e2c1d4e5a8b6f1a2b3c4d5e6f type: string creationTime: examples: - '2026-01-01T12:00:00Z' format: date-time type: string effectiveRefundedAmount: type: string fundsRecoveryId: type: string id: examples: - 018f8c1d-1234-7abc-9def-000000000001 type: string infractionReportId: type: string lastModified: examples: - '2026-01-01T12:30:00Z' format: date-time type: string monitorAccount: examples: - false type: boolean refundAccount: $ref: '#/components/schemas/RefundAccountView' refundAmount: examples: - '1000.00' type: string refundDetails: examples: - refund due to operational failure type: string refundReason: enum: - FRAUD - OPERATIONAL_FLAW - PIX_AUTOMATICO - REFUND_CANCELLED examples: - OPERATIONAL_FLAW type: string refundRejectionReason: enum: - NO_BALANCE - ACCOUNT_CLOSURE - INVALID_REQUEST - OTHER - PARTICIPANT_EXCLUSION type: string refundTransactionId: type: string requestingParticipant: examples: - '12345678' type: string settleReason: type: string settleType: enum: - REFUND - MANUAL type: string status: enum: - OPEN - CLOSED - CANCELLED examples: - OPEN type: string surplusAmount: type: string transactionId: examples: - E12345678202601011200abcdef01234 type: string required: - id - transactionId - refundReason - refundAmount - status - requestingParticipant - contestedParticipant - monitorAccount - creationTime - lastModified type: object LegacyErrorEnvelope: additionalProperties: false properties: code: description: PIX-XXXX error code type: string message: description: Human-readable error message type: string title: description: Short error title type: string required: - code - title - message type: object Detail: additionalProperties: false properties: code: description: >- Stable, machine-readable domain error code scoped to the emitting service (format: -NNNN). examples: - ERR-0001 type: string detail: description: >- A human-readable explanation specific to this occurrence of the problem. examples: - Property foo is required but is missing. type: string errors: description: Optional list of individual error details items: $ref: '#/components/schemas/ErrorDetail' type: - array - 'null' instance: description: >- A URI reference that identifies the specific occurrence of the problem. examples: - https://example.com/error-log/abc123 format: uri type: string status: description: HTTP status code examples: - 400 format: int64 type: integer title: description: >- A short, human-readable summary of the problem type. This value should not change between occurrences of the error. examples: - Bad Request type: string type: default: about:blank description: A URI reference to human-readable documentation for the error. examples: - https://example.com/errors/example format: uri type: string upstream: $ref: '#/components/schemas/Upstream' description: >- RFC 9457 extension member: the error a proxied third-party provider reported. Absent unless the emitting service explicitly surfaced one. type: object RefundAccountView: additionalProperties: false properties: accountNumber: examples: - '123456' type: string accountType: examples: - CACC type: string branch: examples: - '0001' type: string participant: examples: - '99999011' type: string taxIdNumber: examples: - '12345678909' type: string required: - taxIdNumber - participant - branch - accountNumber - accountType type: object ErrorDetail: additionalProperties: false properties: location: description: >- Where the error occurred, e.g. 'body.items[3].tags' or 'path.thing-id' type: string message: description: Error message text type: string value: description: The value at the given location type: object Upstream: additionalProperties: false properties: code: description: The upstream provider's own error code, verbatim. examples: - E4001 type: string message: description: >- The upstream provider's own error message, verbatim (bounded, never its raw response body). examples: - account not found at provider type: string type: object securitySchemes: BearerAuth: bearerFormat: JWT description: JWT bearer token issued by the identity provider. scheme: bearer type: http ````