---
title: "Decode and validate a product barcode (GTIN / UPC-A /..."
method: GET
path: "/api/product/gtin"
tags: ["product"]
---

# Decode and validate a product barcode (GTIN / UPC-A /...

`GET /api/product/gtin`

## Request

- Base URL: `https://2s.io`
- URL: `https://2s.io/api/product/gtin`
- Auth: API key in header `PAYMENT-SIGNATURE`

Decode and validate a product barcode (GTIN / UPC-A / EAN-13 / EAN-8 / GTIN-14 / ISBN-13 / ISSN). Returns the GS1 mod-10 check-digit validation (valid flag + expected digit — an LLM can't reliably compute this), the symbology, the zero-padded GTIN-14 canonical form, and the GS1 prefix decoded to the issuing GS1 member organisation and its country (NOTE: that's the country of the org that issued the prefix, not necessarily where the item was made). Flags restricted-distribution (in-store/variable-measure) prefixes and Bookland (ISBN) / serial (ISSN) ranges. Also attempts a FRESH best-effort product-identity lookup (name, brand, category, image) across the open Open Food/Beauty/Products/Pet Food Facts federation (ODbL) — reliable for food, beverage, and beauty items, sparse for general retail (electronics/apparel), and may be null. Always live (no caching). Set identity=false to skip the lookup and decode only.

## Query parameters

- `gtin` string, required
- `identity` boolean
- `trial` 1

## Other responses

- `200` (unresolved $ref)
- `400`: Invalid request — not charged. error.code: BAD_REQUEST or INVALID_PARAM (parameter validation; error.details.issues lists each problem), MALFORMED_JSON, or a request-specific code. Other client errors: 405 METHOD_NOT_ALLOWED (wrong verb; see the Allow header), 413 PAYLOAD_TOO_LARGE.
- `402`: Payment required. Body is the x402 PaymentRequirements envelope with a multi-network accepts array; the per-call price is in accepts[].amount (and on the operation as x-2s-price). Sign for whichever rail you hold USDC on (EIP-3009 for Base, partial SPL transfer for Solana) and retry with the PAYMENT-SIGNATURE header (X-PAYMENT also accepted for v1 clients). Also PAYMENT_SETTLE_FAILED (error envelope) when a verified payment failed to settle: error.details.chargeStatus is "not_charged" (retry with a fresh payment) or "unknown" (the authorization may still settle before its deadline — check it before retrying).
- `429`: Too many requests — RATE_LIMITED: our per-IP / per-payer limiter. Not charged; retry after Retry-After.
- `5XX`: Server-side failure. 500 INTERNAL: unexpected error; quote error.errorId (also the X-2s-Error-Id header). 502 UPSTREAM_UNAVAILABLE (or another UPSTREAM_* code): the data provider failed — composite endpoints refuse unbilled when every source fails. 503 SERVICE_PAUSED: endpoint paused by the operator kill switch, retry after Retry-After; 503 SPEND_CAP: daily upstream budget exhausted. 504 UPSTREAM_TIMEOUT. Not charged.

---

[API](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api.md) · [All operations](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/llms.txt) · [OpenAPI document](https://skmtc.dev/2s-io/apis/2s-the-most-everything-api/revisions/da4c5caf686e?raw)