Digital Link & resolution

A Digital Link identifier maps a GS1 01 (GTIN) / 21 (serial) pair to a product, so a scanner in the outside world can resolve the published passport. Registration is deliberate, creating a product does not register it.

Registration

POST /products/{id}/publish-dpp is the step that registers the identifier (dpp_identifiers count 0 → 1). Only after this does the item resolve.

Resolution

GET /api/v2/01/{gtin}/21/{serial}                      → 302 to /p/{productId}   (measured 0.16s)
GET /api/v2/01/{gtin}/21/{serial}
    Accept: application/linkset+json                    → GS1 KAV linkset
GET /api/v2/public/passport/{uid}                       → audience-filtered passport JSON
GET /api/v2/public/passport/{uid}/verify                → signature + anchor verification

Typed failures you can branch on

Audience tiers

Public reads are audience-filtered. Anonymous callers get the consumer minimum; only a cryptographically verified X-DPP-Access-Token elevates disclosure. Self-declared hints (e.g. ?viewer=) never do. Every public read is logged with its audience.