Id Gs1
by Duo Data Utilities in Documents & files
Validate and convert GS1 identifiers: GTIN-8, GTIN-12 (UPC-A), GTIN-13 (EAN-13), GTIN-14, GLN and SSCC. Returns the check-digit verdict, the computed correct check digit, the GTIN-14 form with its indicator digit, and conversion between GTIN-8, GTIN-12, GTIN-13 and GTIN-14. No company-prefix split is returned: GS1's prefix-length table is no longer public data. Also computes a missing check digit from a partial code. Structure only, no product database.
https://api.duoleads.com/v1/id/gs1- Price
- $0.05
- per call in USDC
- Uptime
- 100%
- last 30 days
- Response time
- 503 ms
- 775 ms slowest 5%
- Last check
- Passed
- 4 h ago, next any minute now
Reliability
How to call it
GET https://api.duoleads.com/v1/id/gs1
Each call costs $0.05 in USDC on Base, paid with the request over x402.
Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.
Example request
From the listing.
GET https://api.duoleads.com/v1/id/gs1?value=5901234123457Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
op | string | No | validate (default), checkdigit (compute the missing final digit) or convert. One of: validate, checkdigit, convert. Default: "validate". |
to | string | No | Target format. Required when op=convert. One of: gtin8, gtin12, gtin13, gtin14. |
value | string | Yes | GS1 code, digits with optional spaces or hyphens. For op=checkdigit, omit the final digit. |
Example response
The provider's example. We can't check it without paying.
{
"data": {
"also_valid_as": [
"gln"
],
"check_digit": "7",
"check_digit_ok": true,
"gtin14": "05901234123457",
"indicator": "0",
"normalised": "5901234123457",
"reason": null,
"type": "gtin13",
"valid": true
},
"meta": {
"computed_at": "2026-09-28T12:00:00.000Z",
"deterministic": true,
"disclaimer": "Factual output of a deterministic computation over public data. Provided as is, with no warranty of accuracy, completeness or availability. Not investment, financial, legal, tax, medical or any other professional advice, and not a recommendation. Verify before relying on it. Terms: https://api.duoleads.com/terms",
"price_usd": "0.05",
"request_id": "01K6B7Q4ZC8H3F2M9WXR5TYN0D"
},
"ok": true,
"route": "/v1/id/gs1",
"version": "1.0.0"
}Call it from code
The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.05.
curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://api.duoleads.com/v1/id/gs1?value=5901234123457'
# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://api.duoleads.com/v1/id/gs1?value=5901234123457' \
| grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decodeJavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";
// Pays at most $0.05 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.05" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);
// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.05 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.duoleads.com%2Fv1%2Fid%2Fgs1
const res = await pay("https://api.duoleads.com/v1/id/gs1?value=5901234123457");
console.log(res.status, await res.text());Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client
# Pays at most $0.05 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.05"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))
with x402_requests(client) as session:
res = session.get("https://api.duoleads.com/v1/id/gs1?value=5901234123457")
print(res.status_code, res.text)Security scan
No findings
We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.
Recent checks
| When | Result | HTTP | Time | Price |
|---|---|---|---|---|
| 4 h ago | Passed | 402 | 414 ms | $0.05 |
| 9 h ago | Passed | 402 | 538 ms | $0.05 |
| 13 h ago | Passed | 402 | 445 ms | $0.05 |
| 17 h ago | Passed | 402 | 437 ms | $0.05 |
| 21 h ago | Passed | 402 | 720 ms | $0.05 |
Show 10 older checks
| 25 h ago | Passed | 402 | 670 ms | $0.05 |
| 29 h ago | Passed | 402 | 559 ms | $0.05 |
| 33 h ago | Passed | 402 | 529 ms | $0.05 |
| 37 h ago | Passed | 402 | 427 ms | $0.05 |
| 41 h ago | Passed | 402 | 655 ms | $0.05 |
| 45 h ago | Passed | 402 | 469 ms | $0.05 |
| 2 days ago | Passed | 402 | 117 ms | $0.05 |
| 2 days ago | Passed | 402 | 832 ms | $0.05 |
| 2 days ago | Passed | 402 | 519 ms | $0.05 |
| 3 days ago | Passed | 402 | 454 ms | $0.05 |