> ## Documentation Index > Fetch the complete documentation index at: https://docs.closient.com/llms.txt > Use this file to discover all available pages before exploring further. # Generate a single GS1 DataMatrix > Render a GS1 DataMatrix for a GTIN plus any subset of (lot, serial, expiry). At least one of lot or serial is required. Returns image bytes (``image/svg+xml``, ``image/png``, or ``application/pdf``). **Caching**: responses are deterministic given the request body. The endpoint sets ``Cache-Control: public, max-age=2592000`` (30 days) and a strong ``ETag`` over the image bytes. Clients sending ``If-None-Match`` with a matching ETag get ``304 Not Modified``. ## OpenAPI ````yaml /openapi/openapi-products.json post /products/api/v1/datamatrix/ openapi: 3.1.0 info: title: Products API version: 1.0.0 description: > Look up, claim, and browse GTINs in the Closient product repository. ## Authentication All endpoints require an API key passed via the `X-API-Key` HTTP header, unless otherwise noted. ``` X-API-Key: csb__ ``` Generate API keys in **Settings > API Keys** in your dashboard, or via the Account API. Session-based (cookie) authentication is also accepted for browser-based access. ## Rate Limits | Tier | Requests / minute | Requests / day | |-------------|-------------------|----------------| | Default | 300 | 10,000 | | Custom | Contact us | Contact us | Rate-limit headers are included on every response so callers can self-throttle without hitting our 429s ("informed governor"): - `RateLimit-Policy` — every active window, e.g. `300;w=60, 10000;w=86400` - `RateLimit-Limit` — quota for the **most-restrictive** currently-active window - `RateLimit-Remaining` — requests left in that window - `RateLimit-Reset` — seconds until that window resets (relative; clock-skew safe) Legacy `X-RateLimit-*` aliases are also emitted for back-compat. `X-RateLimit-Reset` keeps the absolute Unix-timestamp shape to avoid breaking existing consumers. When rate-limited, you receive `429 Too Many Requests` with a `retry_after_seconds` field in the error envelope and a `Retry-After` header. ## Pagination List endpoints return paginated results in this envelope: ```json { "data": [...], "pagination": { "page": 1, "page_size": 25, "total_count": 342, "total_pages": 14, "has_next": true, "has_previous": false } } ``` Use `?page=2&page_size=50` query parameters. Maximum page size is 100. ## Error Responses All errors conform to [RFC 9457 Problem Details](https://www.rfc-editor.org/rfc/rfc9457) with `Content-Type: application/problem+json`: ```json { "type": "https://closient.com/docs/errors/not_found", "title": "Not Found", "status": 404, "detail": "The requested resource was not found.", "error_code": "not_found", "retryable": false, "timestamp": "2026-03-31T12:00:00+00:00" } ``` Common error codes: `unauthorized` (401), `forbidden` (403), `not_found` (404), `validation_error` (422), `rate_limited` (429), `internal_error` (500). termsOfService: https://www.closient.com/terms/ servers: - url: https://www.closient.com security: [] tags: - name: Products description: Look up, claim, and browse products and trade items. - name: Product Group description: Manage GDSN packaging hierarchy relationships. - name: Import description: Bulk import products from CSV files. - name: QR description: Generate QR codes encoding GS1 Digital Link URLs. - name: Codes description: Generate GS1 DataMatrix and 1D barcodes (EAN/UPC/ITF-14/Code128). - name: Digital Link description: >- Parse GS1 Digital Link URIs into structured AIs (GTIN, lot, expiry, serial). - name: Labels description: >- Bulk label-export jobs: ZIPs of QR / DataMatrix / 1D symbols and multi-up sheet PDFs, async via Celery with status polling. externalDocs: description: Closient Documentation url: https://docs.closient.com paths: /products/api/v1/datamatrix/: post: tags: - Codes summary: Generate a single GS1 DataMatrix description: >- Render a GS1 DataMatrix for a GTIN plus any subset of (lot, serial, expiry). At least one of lot or serial is required. Returns image bytes (``image/svg+xml``, ``image/png``, or ``application/pdf``). **Caching**: responses are deterministic given the request body. The endpoint sets ``Cache-Control: public, max-age=2592000`` (30 days) and a strong ``ETag`` over the image bytes. Clients sending ``If-None-Match`` with a matching ETag get ``304 Not Modified``. operationId: apps_products_api_codes_api_generate_datamatrix parameters: [] requestBody: content: application/json: schema: $ref: '#/components/schemas/DataMatrixPayload' required: true responses: '200': description: OK content: application/json: schema: format: binary title: Response type: string '304': description: Not Modified '422': description: Unprocessable Content content: application/json: schema: $ref: '#/components/schemas/ErrorOut' security: - APIKeyHeaderAuth: [] - OAuthTokenAuth: [] - SessionAuth: [] components: schemas: DataMatrixPayload: description: Request body for synchronous GS1 DataMatrix generation. examples: - expiry: '270630' format: svg gtin: '00012345678905' lot: LOT-A001 serial: SN-0001 properties: gtin: description: GTIN (8/12/13/14 digits, normalized to GTIN-14). title: Gtin type: string lot: anyOf: - type: string - type: 'null' description: Optional GS1 AI(10) lot/batch (1-20 printable ASCII). title: Lot serial: anyOf: - type: string - type: 'null' description: Optional GS1 AI(21) serial (1-20 printable ASCII). title: Serial expiry: anyOf: - type: string - type: 'null' description: Optional GS1 AI(17) expiry as YYMMDD (e.g. '270630' for 2027-06-30). title: Expiry format: default: svg description: >- Output image format. ``svg`` is the default scalable vector output; ``png`` is raster output; ``pdf`` is single-page vector PDF for print workflows (C-2852) — path operators in the content stream rather than a rasterised preview, so a print shop can scale to its target label size at the press. enum: - svg - png - pdf title: Format type: string required: - gtin title: DataMatrixPayload type: object ErrorOut: description: |- RFC 9457 Problem Details response. All API errors are returned in this format with Content-Type: application/problem+json. examples: - detail: The requested resource was not found. error_code: not_found retryable: false status: 404 timestamp: '2026-03-31T12:00:00+00:00' title: Not Found type: https://closient.com/docs/errors/not_found - detail: Validation error. details: - loc: - body - name msg: Field required type: missing error_code: validation_error retryable: false status: 422 timestamp: '2026-03-31T12:00:00+00:00' title: Validation Error type: https://closient.com/docs/errors/validation_error - detail: Rate limit exceeded. Please try again later. error_code: rate_limited retry_after: 31 retryable: true status: 429 timestamp: '2026-03-31T12:00:00+00:00' title: Rate Limited type: https://closient.com/docs/errors/rate_limited properties: type: description: URI reference identifying the error type. title: Type type: string title: description: Short human-readable summary of the error. title: Title type: string status: description: HTTP status code. title: Status type: integer detail: description: Human-readable explanation of this specific occurrence. title: Detail type: string error_code: description: Machine-readable error code (e.g. not_found, unauthorized). title: Error Code type: string retryable: default: false description: Whether retrying the same request can succeed. title: Retryable type: boolean timestamp: description: ISO 8601 timestamp of when the error occurred. title: Timestamp type: string retry_after: anyOf: - type: integer - type: 'null' description: Seconds to wait before retrying (when applicable). title: Retry After owner_action_required: anyOf: - type: boolean - type: 'null' description: Whether the error requires account owner intervention. title: Owner Action Required details: description: Additional context (validation errors, etc.). title: Details required: - type - title - status - detail - error_code - timestamp title: ErrorOut type: object securitySchemes: APIKeyHeaderAuth: type: apiKey in: header name: X-API-Key OAuthTokenAuth: type: http scheme: bearer SessionAuth: type: apiKey in: cookie name: sessionid ````