> ## Documentation Index > Fetch the complete documentation index at: https://docs-pos.solya.app/llms.txt > Use this file to discover all available pages before exploring further. # Process a return (retour / avoir) > Processes a refund (retour) of selected lines from an original charge transaction (vente), at the price they were sold, and settles the money back through the chosen `refundMethod` (201). `refundMethod` is one of: `cash` (drawer pay-out), `card` (reversal to the payment card), `store_credit` (an in-store avoir / credit note), or `exchange` (goods swapped, no money moved). Reach for it to refund or exchange goods at the counter. A `cash` refund debits the store's active register drawer and the returned units re-increment on-hand stock (both idempotent by the return id). Note: `store_credit` RECORDS the refund as an avoir here but does NOT mint the redeemable instrument — issuing the spendable credit note / gift card is a SEPARATE call (the giftcard/credits domain). Failure conditions: 400 on a malformed body; 404 when the `originalTransactionId` names no known charge; 409 when the return `id` already exists; 422 when the return breaks an invariant (e.g. returning more units than were sold). ## OpenAPI ````yaml /openapi.json post /v1/returns openapi: 3.0.3 info: title: Solya POS API version: 1.0.0 description: >- The Solya POS backend HTTP surface. Every documented operation is agent-ready: it carries an `operationId`, an agent-facing `description`, the `pos.*` scopes it enforces (`x-required-permissions`) and an `x-agent-tier`. Success responses return the payload as raw JSON; failures return the `ErrorResponse` envelope (`{ error: { code, message, statusCode } }`). servers: - url: / description: The backend, relative to its deployed origin. security: [] paths: /v1/returns: post: tags: - Returns summary: Process a return (retour / avoir) description: >- Processes a refund (retour) of selected lines from an original charge transaction (vente), at the price they were sold, and settles the money back through the chosen `refundMethod` (201). `refundMethod` is one of: `cash` (drawer pay-out), `card` (reversal to the payment card), `store_credit` (an in-store avoir / credit note), or `exchange` (goods swapped, no money moved). Reach for it to refund or exchange goods at the counter. A `cash` refund debits the store's active register drawer and the returned units re-increment on-hand stock (both idempotent by the return id). Note: `store_credit` RECORDS the refund as an avoir here but does NOT mint the redeemable instrument — issuing the spendable credit note / gift card is a SEPARATE call (the giftcard/credits domain). Failure conditions: 400 on a malformed body; 404 when the `originalTransactionId` names no known charge; 409 when the return `id` already exists; 422 when the return breaks an invariant (e.g. returning more units than were sold). operationId: processReturn requestBody: required: true content: application/json: schema: type: object properties: id: type: string minLength: 1 number: type: string minLength: 1 storeId: type: string minLength: 1 sellerId: type: string minLength: 1 customerId: nullable: true type: string minLength: 1 originalTransactionId: type: string minLength: 1 refundMethod: type: string enum: - cash - card - store_credit - exchange reason: nullable: true type: string minLength: 1 lines: minItems: 1 type: array items: type: object properties: skuId: type: string pattern: ^[0-9a-f]{64}$ quantity: type: integer minimum: 0 exclusiveMinimum: true maximum: 9007199254740991 required: - skuId - quantity required: - id - number - storeId - sellerId - originalTransactionId - refundMethod - lines example: id: ret-ok number: R-ret-ok storeId: store-1 sellerId: seller-1 customerId: null originalTransactionId: sale-return-seed refundMethod: cash reason: damaged lines: - skuId: >- f139995b359e2702f33b391acb3d42a419197a7b2c09d04c1fe6d97ecefe4feb quantity: 1 responses: '201': description: >- The processed return: the signed refund transaction plus its refund metadata. content: application/json: schema: type: object properties: transaction: type: object properties: id: type: string number: type: string storeId: type: string sellerId: type: string customerId: nullable: true type: string status: type: string type: type: string lines: type: array items: type: object properties: skuId: type: string pattern: ^[0-9a-f]{64}$ quantity: type: integer minimum: 0 exclusiveMinimum: true maximum: 9007199254740991 unitPrice: type: number minimum: 0 serial: type: object properties: serialNumber: type: string minLength: 1 warrantyMonths: type: integer minimum: 0 maximum: 9007199254740991 required: - serialNumber - warrantyMonths additionalProperties: false required: - skuId - quantity - unitPrice additionalProperties: false totals: type: object properties: subtotal: type: integer minimum: -9007199254740991 maximum: 9007199254740991 total: type: integer minimum: -9007199254740991 maximum: 9007199254740991 itemCount: type: integer minimum: -9007199254740991 maximum: 9007199254740991 lineCount: type: integer minimum: -9007199254740991 maximum: 9007199254740991 required: - subtotal - total - itemCount - lineCount additionalProperties: false required: - id - number - storeId - sellerId - customerId - status - type - lines - totals additionalProperties: false originalTransactionId: type: string refundMethod: type: string enum: - cash - card - store_credit - exchange reason: nullable: true type: string required: - transaction - originalTransactionId - refundMethod - reason additionalProperties: false description: >- The processed return: the signed refund transaction plus its refund metadata. example: transaction: id: ret-ok number: R-ret-ok storeId: store-1 sellerId: seller-1 customerId: null status: completed type: return lines: - skuId: >- f139995b359e2702f33b391acb3d42a419197a7b2c09d04c1fe6d97ecefe4feb quantity: 1 unitPrice: 1800 totals: subtotal: 1800 total: -1800 itemCount: 1 lineCount: 1 originalTransactionId: sale-return-seed refundMethod: cash reason: damaged '400': description: >- The request failed schema validation; `error.fieldErrors` lists the fields. content: application/json: schema: $ref: '#/components/schemas/ValidationErrorResponse' '401': description: No valid credential was presented — send a bearer token. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: The actor is authenticated but lacks the required `pos.*` scope. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '409': description: >- The request conflicts with current state (duplicate id or stale version). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '422': description: The request is well-formed but violates a domain rule. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: An unexpected server error — safe to retry idempotent requests. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - bearerAuth: [] components: schemas: ValidationErrorResponse: type: object required: - error additionalProperties: false description: >- A `VALIDATION_FAILED` envelope carrying the offending fields in `fieldErrors`. properties: error: type: object required: - code - message - statusCode additionalProperties: false properties: code: type: string enum: - VALIDATION_FAILED message: type: string statusCode: type: integer fieldErrors: type: array description: >- One entry per rejected field: the field path and why it was rejected. items: type: object required: - field - message additionalProperties: false properties: field: type: string description: Dot-path of the offending field. message: type: string description: Why the field was rejected. ErrorResponse: type: object required: - error additionalProperties: false description: The uniform failure envelope every non-2xx response returns. properties: error: type: object required: - code - message - statusCode additionalProperties: false properties: code: type: string enum: - VALIDATION_FAILED - UNAUTHORIZED - FORBIDDEN - NOT_FOUND - CONFLICT - BUSINESS_RULE_VIOLATION - INTERNAL_ERROR description: >- Machine-readable kernel `ResultCode` — branch on this, not on `message`. message: type: string description: >- Human-readable explanation. Safe to surface; never leaks server internals. statusCode: type: integer description: >- The HTTP status, mirrored into the body so a client need not read headers. securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- `Authorization: Bearer `. Accepts EITHER a Keycloak access token (scopes-in-token) OR an opaque POS session token; both resolve to the same `pos.*` scope vocabulary the route guards enforce. ````