# GTIN / Barcode Checksum Validator

> GTIN / Barcode Checksum Validator is a paid API for AI agents from x402-datashop-production.up.railway.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Validates EAN-8, UPC-A, EAN-13, and GTIN-14 barcode numbers using GS1 mod-10 weighted checksum, returning validity, format, GS1 prefix, and computed check digit.

## Facts

- Endpoint: GET https://x402-datashop-production.up.railway.app/v1/logistics/gtin-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gtin-barcode-checksum-validator-c0147e99
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bePPH0nRw2u7RmF-VoWUh

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability gtin-barcode-checksum-validator-c0147e99
```

Example prompt: Can you check if barcode 4006381333931 is a valid GTIN before I upload this product to Amazon — I need to know if it passes the GS1 checksum and what format it is?

## When to prefer this

Use this endpoint when you need to verify GTIN/barcode integrity offline before submitting product listings to marketplaces like Amazon or Google that reject invalid GTINs. Ideal for bulk supplier catalog validation pipelines or pre-publication checks. Cheaper and faster than calling a full product database lookup when you only need checksum verification.

## Known failure modes

- Missing gtin parameter returns 400 or error response
- Non-numeric or wrong-length input may return invalid flag rather than error
- Network timeout on cold start of Railway container
- Barcode with non-digit characters beyond spaces/dashes may fail parsing

## How this service works

Offline validation of product barcode numbers: EAN-8, UPC-A, EAN-13 and GTIN-14, using the GS1 mod-10 weighted checksum. Catches corrupted GTINs in supplier catalogs before marketplace publication (Amazon/Google reject invalid GTINs). Query: ?gtin=4006381333931. Returns valid flag, detected format, GS1 member-org prefix and the computed check digit. Deterministic, cached 1 year.

## Output

Returns a JSON object with a valid boolean flag, the detected barcode format (EAN-8, UPC-A, EAN-13, or GTIN-14), the GS1 member-organization prefix, and the computed check digit. Response is deterministic and cached for 1 year.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "gtin"
     ],
     "properties": {
      "gtin": {
       "type": "string",
       "description": "Barcode number: 8, 12, 13 or 14 digits (spaces/dashes tolerated)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gtin-barcode-checksum-validator-c0147e99/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-datashop-production.up.railway.app](https://www.zero.xyz/host/x402-datashop-production.up.railway.app/llms.txt)