The GS1 Digital Link Resolver, Explained (with a live example)

Most explainers about Digital Product Passport QR codes stop at "scan the code, open a website." That misses the interesting part. The QR code on a compliant product encodes a GS1 Digital Link, and the component that makes it useful is the resolver — the service that turns one product identifier into many different, context-aware responses.

This article shows what the resolver actually does, with a live passport you can call right now (no signup, no key).

What a GS1 Digital Link actually is

A GS1 Digital Link is a normal HTTPS URL that embeds GS1 identifiers as path segments, each tagged with an Application Identifier (AI):

https://id.gs1.org/01/09520000000011/21/DEMO-BAT-01
                   └─01─┘ └──GTIN───┘ └21┘ └─serial─┘

01 → GTIN (Global Trade Item Number) — which product
21 → serial — which individual unit
10 → batch/lot (alternative to serial)

Because it is a plain URL, any phone camera opens it. Because it is structured, machines can parse it. That dual nature is the whole point.

The resolver: one URI, many answers

A dumb QR code returns one fixed page. A resolver inspects the request and returns the representation that fits the caller:

a consumer with a phone browser gets a human-readable HTML page;
a recycler's system asks for JSON-LD and gets machine-readable structured data;
an authority can request the full linkset — every typed link the product exposes.

Same URL, different responses, decided by the Accept header (or a ?format= override).

A live resolver you can call right now

qr3.app hosts a public demo battery passport. Open it in a browser:

https://qr3.app/dpp/09520000000011/DEMO-BAT-01

You will see the consumer page for EcoMax 5000 (Demo) by GreenPower GmbH. Now ask the same URL for machine-readable JSON-LD:

curl "https://qr3.app/dpp/09520000000011/DEMO-BAT-01?format=jsonld"

{
  "@context": ["https://schema.org", "https://gs1.org/voc/"],
  "@type": "Product",
  "gtin": "09520000000011",
  "name": "EcoMax 5000 (Demo)"
}

That is the resolver doing its job: one identifier, a human page and a JSON-LD document built on schema.org + the GS1 web vocabulary. Other representations are available the same way — ?format=json (raw passport), ?format=linkset (all typed links), ?format=dcat-ap — or via standard Accept negotiation (Accept: application/ld+json).

Validate identifiers before you mint links

A resolver is only as trustworthy as the identifiers behind it. Validate a GTIN before you build a Digital Link for it:

import { QR3 } from "@qr3/sdk";

const client = new QR3({ apiKey: process.env.QR3_API_KEY! });

const result = await client.gs1.validateGs1({
  identifier_type: "gtin",
  value: "09520000000011",
});

console.log(result.valid);   // true
console.log(result.detail);  // "Valid GTIN-14"

Register your GTINs

Keep the identifiers you use under management so every Digital Link traces back to a known product:

const gtin = await client.gs1.createGs1Identifier({
  identifier_type: "gtin", // or "gln" | "company_prefix"
  value: "09520000000011",
  label: "EcoMax 5000",
});

Using qr3 as your resolver

You do not have to build and operate a resolver yourself. Point your product QR code at the Digital Link, host the passport on qr3.app, and the resolver serves the right representation per request. The GTIN/serial in the URL stay stable forever (so printed labels never break), while the data behind them stays updatable.

FAQ

Is the QR code itself different from a normal one? No — it is a standard QR (or Data Matrix) carrying a GS1 Digital Link URL. Any camera opens it; the intelligence is in the resolver, not the symbol.

Do consumers and recyclers really get different content? Yes — that is content negotiation. The browser gets HTML; a system requesting application/ld+json (or ?format=jsonld) gets structured data from the same URL.

Can I keep my own product page and still be compliant? Yes. The Digital Link can expose multiple typed links (a linkset) — your marketing page, the official passport, a recycling datasheet — each tagged with a link type.

Sources

Try the live passport above, then start for free and resolve your own.

These are working demos with fictitious product data and example GTINs from GS1 prefix 952. They do not represent assigned product identifiers, a registry entry or a certification.