> ## Documentation Index > Fetch the complete documentation index at: https://www.twicecommerce.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Validate a discount code against an order context > Dry-run validation of a code against an order context: checks the validity window, usage limits and applicability, and returns the computed effect without consuming a use. Applying for real happens via the order applyOrderDiscountCode endpoint. ## OpenAPI ````yaml https://server.twicecommerce.com/api/admin/openapi-mintlify.json post /v1/admin/discount-codes/validate openapi: 3.0.2 info: title: TWICE Admin API description: "The TWICE Admin API is the merchant-facing API of the Twice platform. It is currently in alpha: endpoints and schemas may change without notice.\n\n## Webhooks\n\nWebhooks notify your systems when resources change in Twice. A webhook subscription pairs one event type with one HTTPS endpoint of yours; whenever a matching event occurs, we POST the event to that endpoint. Subscriptions and their delivery logs are managed in the Twice admin under **Account → Integrations**.\n\n### Event types\n\n- `order.created`\n- `order.deleted`\n- `order.updated`\n\n### Payload\n\nEvery delivery is an HTTP POST with a JSON body sharing a common envelope. The typed payload of each event type is documented in the **Webhooks** section of the sidebar.\n\n```json\n{\n\t\"eventId\": \"5f2eb3a6-6cbd-4a2e-9350-6e0d1e2f9a11\",\n\t\"eventType\": \"order.created\",\n\t\"eventTime\": \"2026-08-06T12:34:56.789Z\",\n\t\"resource\": \"order\",\n\t\"resourceId\": \"0d9e0a7c-3fd1-4c8f-9c0d-2b7c6f7f2a55\",\n\t\"apiVersion\": \"2025-06\",\n\t\"data\": { \"…\": \"the API representation of the resource, or null for deletes\" }\n}\n```\n\n`data` carries the resource in the same shape the REST API returns it, as of the API version in `apiVersion`. Each subscription is pinned to the API version that was the latest when the subscription was created, so a new API version never changes the payload shape you receive — moving to a newer version is an explicit update of the subscription.\n\n### Acknowledging deliveries\n\nRespond with any **2xx** status to acknowledge a delivery. Any other status — or a timeout — counts as a failed attempt. Respond as quickly as possible and do heavy processing asynchronously after acknowledging.\n\n### Delivery semantics\n\nDeliveries are **at-least-once**: the same event can occasionally be delivered more than once, so deduplicate on the `X-Twice-Event-Id` header (or the equal `eventId` body field). Ordering is not guaranteed — when it matters, use `eventTime` or re-fetch the current state of the resource via the API.\n\n### Retries\n\nFailed deliveries are retried up to 3 times (4 attempts in total) with growing backoff — roughly 10 s, 20 s, 40 s after the preceding attempt — giving up 10 minutes after the first attempt. After 3 consecutive events fail all their attempts, the subscription is automatically disabled (`disabledReason: TOO_MANY_FAILED_DELIVERY_ATTEMPTS`) and must be re-enabled manually in the admin. Individual deliveries can also be redelivered manually from the delivery log.\n\n### Verifying signatures\n\nEach subscription has a signing secret (prefixed `whsec_`), available in the admin. Deliveries carry an HMAC-SHA256 signature of the exact raw request body in the `X-Twice-Signature` header, formatted `sha256=`. Verify it against the raw body bytes — parse the JSON only after the signature checks out:\n\n```js\nimport { createHmac, timingSafeEqual } from 'node:crypto';\n\nconst expected = 'sha256=' + createHmac('sha256', secret).update(rawBody, 'utf8').digest('hex');\nconst signature = req.headers['x-twice-signature'];\nconst isValid =\n\ttypeof signature === 'string' &&\n\tsignature.length === expected.length &&\n\ttimingSafeEqual(Buffer.from(signature), Buffer.from(expected));\n```" version: 2025-06 servers: - url: https://server.twicecommerce.com security: - ApiKeyAuth: [] paths: /v1/admin/discount-codes/validate: post: tags: - discountCodes summary: Validate a discount code against an order context description: >- Dry-run validation of a code against an order context: checks the validity window, usage limits and applicability, and returns the computed effect without consuming a use. Applying for real happens via the order applyOrderDiscountCode endpoint. operationId: admin.discountCodes.validate parameters: [] requestBody: description: Body content: application/json: schema: type: object properties: code: type: string minLength: 1 maxLength: 64 items: type: object properties: id: type: string catalogItemId: nullable: true type: string purchaseType: nullable: true type: string enum: - booking - sale - subscription - buyback startDate: nullable: true type: string format: date-time pattern: >- ^(?:(?:\d\d[2468][048]|\d\d[13579][26]|\d\d0[48]|[02468][048]00|[13579][26]00)-02-29|\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\d|30)|(?:02)-(?:0[1-9]|1\d|2[0-8])))T(?:(?:[01]\d|2[0-3]):[0-5]\d(?::[0-5]\d(?:\.\d+)?)?(?:Z))$ collectionIds: nullable: true type: array items: type: string subtotal: type: integer minimum: 0 maximum: 9007199254740991 required: - purchaseType - subtotal required: - code - items responses: '200': description: '200' content: application/json: schema: anyOf: - type: object properties: valid: type: boolean enum: - true code: type: object properties: id: type: string code: type: string valueType: type: string enum: - percentage - fixed_per_order - fixed_per_item value: type: integer minimum: -9007199254740991 maximum: 9007199254740991 applicablePurchaseTypes: nullable: true type: array items: type: string enum: - sale - booking - subscription required: - id - code - valueType - value - applicablePurchaseTypes additionalProperties: false appliedValue: type: integer minimum: -9007199254740991 maximum: 9007199254740991 allocations: type: array items: type: object properties: itemId: type: string value: type: integer minimum: 0 maximum: 9007199254740991 required: - itemId - value additionalProperties: false required: - valid - code - appliedValue additionalProperties: false - type: object properties: valid: type: boolean enum: - false reason: type: string enum: - invalid - not_found - disabled - usage_limit_reached - internal_code - not_yet_valid - expired - catalog_item_not_applicable - collection_not_applicable - location_not_applicable - not_combinable - worse_deal - already_applied - purchase_type_mismatch - no_eligible_items - no_effect message: type: string required: - valid - reason - message additionalProperties: false '400': description: '400' '401': description: '401' '403': description: '403' '404': description: '404' '429': description: '429' '500': description: '500' components: securitySchemes: ApiKeyAuth: type: apiKey name: X-API-KEY in: header description: API key for the Twice API ````