> ## 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. # Apply an authorised discount to a whole ticket > Applies a manager-authorised reduction to the WHOLE ticket and persists the traced record. This is the deliberate, one-off human decision — reach for it only when no automatic promotion or presented coupon covers the case, and never to reproduce an offer that should be a rule (`POST /v1/promotions`) or a code (`POST /v1/coupons`). You supply the `id`, which is the IDEMPOTENCY ANCHOR: a second post of the same id is rejected 409 rather than doubling the reduction, so generate one id per intended discount and retry with the same one. `reason` is a closed vocabulary (`manual_markdown`, `promotional`, `loyalty_reward`, `damaged_goods`, `manager_goodwill`) and `note` carries up to 280 characters of free-text justification. Express the reduction either as `basis:'percent'` with `percentBps` in BASIS POINTS (1000 = 10%) or `basis:'amount'` with `amountCents` in integer CENTS; the `cart` snapshot you pass is what the gross is computed from, and it is read, never mutated. The default policy caps a discount at 50% and at 50.00 € and refuses a reduction larger than the base — breaching any of those gives 422, which means 'the request was well-formed but too deep', not a malformed body. Applying a discount records it; it does not settle a sale, which stays `POST /v1/checkout/finalize`. ## OpenAPI ````yaml /openapi.json post /v1/discounts/ticket 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/ticket: post: tags: - Promotions summary: Apply an authorised discount to a whole ticket description: >- Applies a manager-authorised reduction to the WHOLE ticket and persists the traced record. This is the deliberate, one-off human decision — reach for it only when no automatic promotion or presented coupon covers the case, and never to reproduce an offer that should be a rule (`POST /v1/promotions`) or a code (`POST /v1/coupons`). You supply the `id`, which is the IDEMPOTENCY ANCHOR: a second post of the same id is rejected 409 rather than doubling the reduction, so generate one id per intended discount and retry with the same one. `reason` is a closed vocabulary (`manual_markdown`, `promotional`, `loyalty_reward`, `damaged_goods`, `manager_goodwill`) and `note` carries up to 280 characters of free-text justification. Express the reduction either as `basis:'percent'` with `percentBps` in BASIS POINTS (1000 = 10%) or `basis:'amount'` with `amountCents` in integer CENTS; the `cart` snapshot you pass is what the gross is computed from, and it is read, never mutated. The default policy caps a discount at 50% and at 50.00 € and refuses a reduction larger than the base — breaching any of those gives 422, which means 'the request was well-formed but too deep', not a malformed body. Applying a discount records it; it does not settle a sale, which stays `POST /v1/checkout/finalize`. operationId: applyTicketDiscount requestBody: required: true content: application/json: schema: oneOf: - type: object properties: id: type: string minLength: 1 reason: type: string enum: - manual_markdown - promotional - loyalty_reward - damaged_goods - manager_goodwill note: type: string maxLength: 280 cart: type: object properties: lines: type: array items: type: object properties: id: type: string minLength: 1 skuId: nullable: true type: string pattern: ^[0-9a-f]{64}$ quantity: type: integer minimum: 0 exclusiveMinimum: true maximum: 9007199254740991 unitPrice: type: integer minimum: 0 maximum: 9007199254740991 vatRate: type: number minimum: 0 maximum: 100 free: type: boolean required: - id - skuId - quantity - unitPrice - vatRate - free freeLineSequence: type: integer minimum: 0 maximum: 9007199254740991 required: - lines - freeLineSequence basis: type: string enum: - percent percentBps: type: integer minimum: 1 maximum: 10000 required: - id - reason - cart - basis - percentBps - type: object properties: id: type: string minLength: 1 reason: type: string enum: - manual_markdown - promotional - loyalty_reward - damaged_goods - manager_goodwill note: type: string maxLength: 280 cart: type: object properties: lines: type: array items: type: object properties: id: type: string minLength: 1 skuId: nullable: true type: string pattern: ^[0-9a-f]{64}$ quantity: type: integer minimum: 0 exclusiveMinimum: true maximum: 9007199254740991 unitPrice: type: integer minimum: 0 maximum: 9007199254740991 vatRate: type: number minimum: 0 maximum: 100 free: type: boolean required: - id - skuId - quantity - unitPrice - vatRate - free freeLineSequence: type: integer minimum: 0 maximum: 9007199254740991 required: - lines - freeLineSequence basis: type: string enum: - amount amountCents: type: integer minimum: 0 exclusiveMinimum: true maximum: 9007199254740991 required: - id - reason - cart - basis - amountCents example: id: disc-2026-04-17-0142 reason: manual_markdown note: Damaged packaging on the display unit cart: lines: - id: line-1 skuId: null quantity: 2 unitPrice: 1990 vatRate: 20 free: false freeLineSequence: 0 basis: percent percentBps: 1000 responses: '201': description: The persisted discount record, with the valued 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 persisted discount record, with the valued 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' '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. ````