> ## Documentation Index > Fetch the complete documentation index at: https://docs.server.express/llms.txt > Use this file to discover all available pages before exploring further. # Preview what a coupon is worth on a basket > Prices the basket from ids alone (exactly as checkout will) and quotes the code against it. A rejected code is NOT an error: it comes back as 200 with `{ valid: false, reason }`. `planId` is a dedicated plan slug, a TenantOS server id for a one-off stock machine, a cloud plan slug or a hosting plan id. `billingCycle`, `quantity` and `addonIds` only apply to CLOUD. Rate limited to 20 requests per minute per IP. ## OpenAPI ````yaml /api-reference/openapi.yaml post /v1/client/coupons/validate openapi: 3.1.0 info: title: Server.Express API version: 1.0.0 description: >- The customer-facing Server.Express API: auth, billing, tickets, cloud and dedicated servers, hosting, reselling and account management. Every response uses the `{ success, data | error }` envelope. contact: name: Server.Express url: https://server.express servers: - url: https://my.server.express/api description: Production security: - bearerAuth: [] - apiToken: [] tags: - name: API Tokens - name: Account - name: Auth - name: Cloud - name: Coupons - name: Credits - name: Dashboard - name: Dedicated - name: Health - name: Hosting - name: Integrations - name: Invoices - name: Livechat - name: Notifications - name: Passkeys - name: Payments - name: Products - name: Public - name: Public Invoices - name: Public Tools - name: Reseller - name: SSH Keys - name: Services - name: Tasks - name: Teams - name: Tickets - name: Web Hosting - name: Webhooks paths: /v1/client/coupons/validate: post: tags: - Coupons summary: Preview what a coupon is worth on a basket description: >- Prices the basket from ids alone (exactly as checkout will) and quotes the code against it. A rejected code is NOT an error: it comes back as 200 with `{ valid: false, reason }`. `planId` is a dedicated plan slug, a TenantOS server id for a one-off stock machine, a cloud plan slug or a hosting plan id. `billingCycle`, `quantity` and `addonIds` only apply to CLOUD. Rate limited to 20 requests per minute per IP. operationId: publicClientValidateCoupon requestBody: required: true content: application/json: schema: type: object required: - code - productType - planId properties: code: type: string minLength: 1 productType: type: string enum: - DEDICATED - CLOUD - WEB_HOSTING planId: type: string billingCycle: type: string enum: - monthly - quarterly - semi-annually - annually - biennially - triennially quantity: type: integer minimum: 1 maximum: 10 addonIds: type: array items: type: string responses: '200': description: The quote, or the reason the code doesn't apply. content: application/json: schema: type: object required: - success - data properties: success: type: boolean const: true data: oneOf: - type: object required: - valid - code - amountOff - subtotalBefore - subtotalAfter - currency - recurring properties: valid: type: boolean const: true code: type: string description: type: - string - 'null' amountOff: type: integer description: Minor units taken off. subtotalBefore: type: integer description: >- Basket subtotal after any reseller discount, before the coupon. Minor units. subtotalAfter: type: integer description: >- Subtotal after the coupon, before tax. Minor units. currency: type: string recurring: type: boolean description: Whether the discount also applies to renewals. - type: object required: - valid - reason properties: valid: type: boolean const: false reason: type: string '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '409': $ref: '#/components/responses/Conflict' '429': $ref: '#/components/responses/TooManyRequests' '500': $ref: '#/components/responses/ServerError' security: - bearerAuth: [] components: responses: BadRequest: description: Validation failed or the request is malformed. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' Unauthorized: description: Missing, invalid or expired credentials. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' Forbidden: description: >- Authenticated but not allowed (missing scope, not an admin, or not your resource). content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NotFound: description: The resource doesn't exist or isn't visible to you. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' Conflict: description: The request conflicts with the resource's current state. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' TooManyRequests: description: Rate limit exceeded. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' ServerError: description: Unexpected server error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' schemas: ErrorResponse: type: object required: - success - error properties: success: type: boolean const: false error: type: string description: Human-readable error message. additionalProperties: true securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- Session access token (JWT) from POST /v1/auth/login or /v1/auth/refresh. A session satisfies every API scope. apiToken: type: http scheme: bearer bearerFormat: se_live__ description: >- Personal API token created under Settings → API tokens. Only routes guarded by verifyApiAuth accept it, and the token must carry the scope named in the operation's x-required-scope. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.