GETMethod GET/passport/01/{gtin}/proof

You retrieve the public proofs of the passport that this GTIN announces for a model. When you leave this page, you will know how to ask for these proofs from a GTIN alone, how to read what each block establishes, and how to interpret the absence of a block correctly.

Full address:

GET https://api.sealtrust.io/v1/passport/01/{gtin}/proof

The same endpoint also answers without the /v1 prefix, at https://api.sealtrust.io/passport/01/{gtin}/proof. Both addresses call the same code. Use the /v1 form for a new integration.

#Authorization

None, public endpoint. You send no API key, no session and no origin header. The response is the same for everyone.

#Rate limit

60 calls per 60-second window, counted per calling network address.

This counter is shared by every path that starts with /passport. The calls you address to one of them therefore eat into the budget of the others. The /v1 prefix does not create a second budget: /v1/passport/01/03701234567890/proof and /passport/01/03701234567890/proof fill the same counter.

Every accepted response carries three headers.

A refusal returns 429, with these three headers and Retry-After. On this endpoint, Retry-After equals the duration of the window, that is 60 seconds.

#Path and query parameters

This endpoint has no query parameter.

We bring the GTIN back to its canonical 14-digit form before the lookup. We remove every character that is not a digit, then we pad with zeros on the left. A GTIN of 8, 12 or 13 digits therefore finds the same model as a 14-digit GTIN. We refuse with a 404 an empty value, a value with no digit at all, or a value of more than 14 digits.

A GTIN ends with a check digit, the digit computed from the ones that precede it. We check it, and we refuse with a 400 a GTIN whose last digit does not match. Copy the code exactly as it is printed on the product, digit for digit.

The gtin field of the response returns to you the 14-digit form that was kept.

#Headers

No header is required.

#Request body

None. This request has no body.

#Example request

Proofs of the reference passport announced by the GTIN 03701234567890.

curl -i https://api.sealtrust.io/v1/passport/01/03701234567890/proof

const reponse = await fetch(
  "https://api.sealtrust.io/v1/passport/01/03701234567890/proof",
);

if (reponse.status === 404) {
  console.log("Aucun passeport de référence publié pour ce GTIN.");
} else if (reponse.ok) {
  const preuves = await reponse.json();
  console.log(preuves.gtin, preuves.level, preuves.passport_version);
  console.log(preuves.data_hash);
  console.log(preuves.ipfs_gateway_url);
  console.log(preuves.passport_anchor);
  console.log(preuves.seal);
  console.log(preuves.vc);
} else {
  console.log(reponse.status, await reponse.json());
}

import requests

response = requests.get(
    "https://api.sealtrust.io/v1/passport/01/03701234567890/proof",
    timeout=30,
)

if response.status_code == 404:
    print("Aucun passeport de référence publié pour ce GTIN.")
elif response.ok:
    preuves = response.json()
    print(preuves["gtin"], preuves["level"], preuves["passport_version"])
    print(preuves.get("data_hash"))
    print(preuves.get("ipfs_gateway_url"))
    print(preuves.get("passport_anchor"))
    print(preuves["seal"])
    print(preuves["vc"])
else:
    print(response.status_code, response.json())

#Example response

HTTP code 200.

{
  "passport_version": 3,
  "data_hash": "1111111111111111111111111111111111111111111111111111111111111111",
  "ipfs_uri": "ipfs://bafybeiaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
  "ipfs_gateway_url": "https://ipfs.io/ipfs/bafybeiaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
  "passport_anchor": {
    "chain": "base",
    "chain_id": 8453,
    "tx_hash": "0x2222222222222222222222222222222222222222222222222222222222222222",
    "basescan_url": "https://basescan.org/tx/0x2222222222222222222222222222222222222222222222222222222222222222",
    "merkle_root": "0x3333333333333333333333333333333333333333333333333333333333333333",
    "leaf": "0x4444444444444444444444444444444444444444444444444444444444444444",
    "leaf_index": 7,
    "proof": [
      "0x5555555555555555555555555555555555555555555555555555555555555555",
      "0x6666666666666666666666666666666666666666666666666666666666666666"
    ],
    "anchored_at": "2026-08-14T09:12:44.318000+00:00",
    "data_hash_matches": true,
    "proves": "content_existed_at_or_before_tx"
  },
  "seal": {
    "sealed": true,
    "sealed_at": "2026-08-12T10:04:11.882000+00:00",
    "algorithm": "st-dpp-chain-v1",
    "version_hash": "7777777777777777777777777777777777777777777777777777777777777777",
    "prev_version_hash": "8888888888888888888888888888888888888888888888888888888888888888",
    "linked": true,
    "chain_link_match": true
  },
  "vc": {
    "issued": true,
    "vct": "https://schema.sealtrust.io/vct/digital-product-passport",
    "issued_at": "2026-08-12T10:04:12.140000+00:00"
  },
  "level": "model",
  "gtin": "03701234567890"
}

The response also carries the Cache-Control: no-store, max-age=0 header. Do not put this response in any shared cache. To reduce the number of your calls, keep the result in your own application cache, with the freshness window your usage tolerates.

Five fields are always present: passport_version, seal, vc, and, specific to this endpoint, level and gtin. The other fields appear only when the corresponding proof is established. An absence covers two situations that the response does not distinguish: the proof does not exist yet, or we could not establish it at the time of your call. Never read an absence as tampering.

#The passport_anchor block

This block establishes a single thing: the content of this version existed no later than the moment of the transaction. That is what its proves field says, whose value is content_existed_at_or_before_tx. It does not make the content true, and it does not prevent the brand from publishing a correction later.

You can recompute the root yourself. You start from leaf. For each element of proof, in order, you place the two 32-byte values side by side, the smaller of the two first, then you apply keccak256 to the concatenation. The result becomes the new working value. After the last element of proof, you must obtain exactly merkle_root. This is the OpenZeppelin verification convention. We sort the neighbors at each level, so the proof does not need to indicate a direction.

It remains for you to check that merkle_root really is the value written to the chain. Open basescan_url to read the write transaction.

An absent passport_anchor does not mean that the passport is not reliable. Writing to the chain is an operation that SealTrust triggers. A brand does not order it from its console, and many published versions are never written. Publishing a version remains a write to the database, with no transaction on the chain. The seal block, for its part, is present on every sealed version, and it is the one that makes a rewrite visible as long as no chain write covers the version.

#The seal block

We set the seal at the first publication of a version. It chains that version to the previous one of the same passport, which makes visible a rewrite that happened afterwards.

#The vc block

The credential is the passport returned as a signed document, in SD-JWT-VC format. The signing private key does not leave a hardware security module.

#Why ipfs_uri can be missing

We announce the IPFS copy only when we have checked, at the time of your call, that its content is exactly the public passport the brand publishes today. We fetch the copy, we hash it, and we publish the link only if it matches.

Three situations therefore produce a response without ipfs_uri: no copy has been pinned, the copy could not be retrieved at the time of your call, or its content no longer matches what the brand publishes. A brand that changes its access rules changes what its public passport shows, so a copy pinned before that change stops being announced until it has been pinned again. The field does not distinguish these three cases. Never read its absence as proof that the copy has been altered.

#Errors

The body of an error response carries a detail field.

#See also

• GET /passport/01/{gtin}, read the published passport of a model, from its GTIN.
• GET /passport/{identifier}/proof, gather the public proofs of the passport of an item.
• GET /01/{gtin}, resolve a GS1 link that carries only a GTIN.
• Trust and proofs, what each proof establishes and how a third party redoes the verification.