> ## 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. # Get an applied discount by id > Reads back ONE already-applied discount by the `id` the caller chose when applying it — the audit trace, not a configuration. It tells you what was taken off (`amountCents`, SIGNED and `<= 0`), off what gross (`baseCents`), how deep that was (`effectiveBps`), under which coded `reason`, by which `actorId` and at what instant. Use it to justify a reduction that already happened or to confirm an apply landed. There is no list endpoint and no search by ticket: you must already hold the id. This reads MANUAL discounts only — automatic promotions are at `GET /v1/promotions` and promo codes at `GET /v1/coupons`. 404s when no discount carries the id. ## OpenAPI ````yaml /openapi.json get /v1/discounts/{id} 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/discounts/{id}: get: tags: - Promotions summary: Get an applied discount by id description: >- Reads back ONE already-applied discount by the `id` the caller chose when applying it — the audit trace, not a configuration. It tells you what was taken off (`amountCents`, SIGNED and `<= 0`), off what gross (`baseCents`), how deep that was (`effectiveBps`), under which coded `reason`, by which `actorId` and at what instant. Use it to justify a reduction that already happened or to confirm an apply landed. There is no list endpoint and no search by ticket: you must already hold the id. This reads MANUAL discounts only — automatic promotions are at `GET /v1/promotions` and promo codes at `GET /v1/coupons`. 404s when no discount carries the id. operationId: getAppliedDiscount parameters: - schema: type: string minLength: 1 in: path name: id required: true responses: '200': description: >- The traced applied discount, with its attribution and signed reduction. content: application/json: schema: type: object properties: id: type: string scope: type: string enum: - line - ticket lineId: nullable: true type: string basis: type: string enum: - percent - amount baseCents: type: integer minimum: -9007199254740991 maximum: 9007199254740991 amountCents: type: integer minimum: -9007199254740991 maximum: 9007199254740991 effectiveBps: type: integer minimum: -9007199254740991 maximum: 9007199254740991 reason: type: string enum: - manual_markdown - promotional - loyalty_reward - damaged_goods - manager_goodwill note: type: string actorId: type: string at: type: string required: - id - scope - lineId - basis - baseCents - amountCents - effectiveBps - reason - actorId - at additionalProperties: false description: >- The traced applied discount, with its attribution and signed reduction. example: id: disc-2026-04-17-0142 scope: ticket lineId: null basis: percent baseCents: 3980 amountCents: -398 effectiveBps: 1000 reason: manual_markdown note: Damaged packaging on the display unit actorId: usr-manager-3 at: '2026-04-17T14:32:05.000Z' '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' '404': description: No resource matches the addressed identifier. 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. ````