GS1 Digital Link
What Is a DPP Resolver Service?
What a DPP resolver does, how content negotiation works and why a resolver is critical to the lifetime of printed QR codes on your products.
A resolver takes a product identifier and redirects the request to the passport address currently in force. It sounds trivial, but it is one of the most critical pieces of DPP architecture — because the label stays on the product for ten years and the backend behind it does not.
How it works
- The consumer scans the QR; the browser goes to
https://id.brand.com/01/0869.../21/SN42. - The resolver parses the identifier (GTIN + serial).
- It looks up the registered link types and picks the target for this request.
- It usually redirects with HTTP 307.
The target can change over time; the printed URL never does.
Content negotiation
The resolver inspects the request's Accept header:
| Request | Response |
|---|---|
text/html | The consumer-facing passport page |
application/ld+json | Structured passport data |
| A specific link type | The relevant resource (e.g. safety information) |
That is how a single QR serves both people and machines. See JSON-LD and DPP data.
Link types
GS1's link types let one identifier point at several resources: digital product passport, sustainability information, traceability (EPCIS), certification information, safety information, recall status. RFC 9264 linksets support machine discovery. See EPCIS 2.0 and product recalls.
Conformance levels
- Level 0: redirection only.
- Level 1: content negotiation.
- Level 2: full linkset API.
- Level 3: compressed URI support.
For DPPs, level 1 or above is the practical target.
Own resolver or a service?
| Option | Advantage | Risk |
|---|---|---|
| Your own resolver on your own domain | Full control, no lock-in | Operational burden |
| Commercial resolver service | Fast start | Domain dependency |
| Integrated DPP platform | Single point of management | Needs an exit plan |
Whichever you choose, the domain in the printed URL must be under your control. See what a DPP service provider is.
Resolver versus registry
The resolver is the operator's service and routes consumer traffic. The EU DPP Registry is the Commission's index and is what authorities query. They do different jobs. See the EU DPP Registry guide.
Frequently asked questions
Is a resolver mandatory?
The law does not name resolvers; what is mandatory is persistence and the ban on lock-in. A resolver is the most practical way to satisfy both.
Can I use a link shortener?
Not advisable: no persistence guarantee, questionable data sovereignty, and if the service closes every label becomes a dead link.
What if the resolver goes down?
The CIRPASS-2 reference architecture recommends an independent EU fallback resolution service for exactly this. On your side, high availability and caching matter.
