A Digital Product Passport needs a data carrier, and in practice that means a QR code. The question is what the QR code contains. GS1 Digital Link is the answer most of the industry has settled on, and it is worth understanding why, including the part vendors routinely get wrong.
The correction first
You will read that the EU regulation requires GS1 Digital Link. It does not.
ESPR requires a persistent unique product identifier and points to the ISO/IEC 15459 family of identifier standards. It does not name GS1, and it does not name Digital Link.
What is true is narrower and still useful: the EU registry guidance and the European standards for passports point towards URL-based identifiers, and GS1 Digital Link is the established way to express a product identifier as a URL. Retail scanners are moving to read it anyway. So it is the sensible choice. It is not a legal requirement, and a vendor telling you otherwise is either sloppy or selling.
What a Digital Link URL looks like
A Digital Link is an ordinary web address with the product identifier encoded in the path:
https://brand.example.com/01/05712345678904/21/ABC123
The numbers before each segment are GS1 application identifiers. 01 introduces the GTIN, the barcode number. 21 introduces a serial. 10 would introduce a batch.
Two details trip people up. The GTIN is always written as fourteen digits, zero-padded on the left, so a thirteen-digit EAN gains a leading zero. And the whole thing is a working URL: point a phone camera at it and a browser opens.
Why this beats a plain link
A shortened link or a custom URL works until you need the code to do two jobs.
A Digital Link carries the product identifier in a machine-readable form, so a point-of-sale system can read the GTIN out of the same code a customer scans for the passport. That is the point of GS1's Sunrise 2027 initiative: retail scanners worldwide are expected to read 2D codes by the end of 2027, so one code on the care label can serve the till and the consumer.
It also means the code does not depend on a redirect service staying alive. The identifier is in the URL, not in a lookup table somewhere.
What to decide before you print
The identifier granularity. One code per style is easy and nearly useless: a customer scanning a jacket wants the size they are holding, and an EPR report wants quantities per size. One code per size per order is the unit that matches how garments are actually made and sold.
The domain. The URL in the code is a promise you are making for the life of the garment. Serving it from your own domain means the passport stays yours if you change platforms; the identifier does not have to change when the vendor does.
Where the code goes. A care label survives the garment. A hangtag does not. If the passport is meant to be useful for repair, resale or recycling, the carrier needs to last, and that is a conversation with your label supplier rather than your software vendor.
Who owns the GTIN. Your barcode numbers come from your GS1 member organisation and belong to your brand. No passport platform should be issuing them for you, and if one does, ask what happens to those numbers when you leave.
What Seamdex does with it
Every published size gets a Digital Link URL and a QR code, on the platform domain or on your own verified domain. The QR sheets print per size, and the identifier stays stable when you republish a product, so a code already sewn into a garment keeps resolving to the current passport.
That last part is worth stating plainly: publishing a correction does not mint a new code. The garment in someone's wardrobe does not know you fixed a typo, and it should not have to.
Standards references in this note were verified in September 2026. GS1 publishes the Digital Link standard and its resolver standard openly; read them rather than a vendor's summary if you are making an architectural decision.