What is a GS1 Digital Link resolver?

Published October 4, 2026 · Checked against GS1 US guidance and this resolver's behavior

A GS1 Digital Link QR code on a product pack contains a web address that includes the product's GTIN. A resolver is the service at that address: it reads the GTIN (and optionally a batch/lot or serial number) out of the address and sends the person who scanned to the right destination. The code printed on the pack stays the same while the destination can change.

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The address in the QR code

A GS1 Digital Link address is a normal web address whose path carries GS1 identifiers, each introduced by its application identifier number:

https://qr-42.com/01/00000012345007/10/LOT-8891

Part	Meaning
Host	The resolver. Shared qr-42.com, or your own domain on Growth and above.
01	The GTIN, in its 14-digit form. The resolver checks the GS1 check digit and rejects a bad one.
22 / 10 / 21	Optional qualifiers, in that order: product variant (CPV), batch/lot, serial number.

What happens when it's scanned

1. Parse. The resolver validates the GTIN and any qualifiers.
2. Look up. It finds the links you've published for that GTIN on that host.
3. Choose the most specific. A link for a serial number beats one for a lot, which beats one for a product variant, which beats the general GTIN link.
4. Narrow by link type, language and country. By default the shopper gets the consumer product page. The phone's language setting and the approximate country (from the network) pick between the variants you published, falling back to your default.
5. Redirect. The visitor is sent to the destination with an HTTP 307 redirect. Any extra query parameters on the scan are passed through to your page.

If a GTIN hasn't been published on the shared host, the resolver doesn't guess: it answers 404 and points to GS1's own resolver for that GTIN, so a scan of an unclaimed product doesn't dead-end. On a brand-owned domain you can set a home page to redirect to instead.

Why the checkout scanner never needs it

The resolver is for people with phones. A 2D-capable checkout scanner decodes the GTIN straight out of the symbol and makes no network request at all, which is why the same code works at the register and on a shopper's phone. See are stores ready for 2D barcodes.

Machine-readable answers

• Add ?linkType=all to a scan address, or send Accept: application/linkset+json, to get every link for that product as an RFC 9264 linkset instead of a redirect.
• Every scan response carries a Link header pointing at the linkset, and /.well-known/gs1resolver describes the resolver itself.

Try it on the live demo product: qr-42.com/01/00000012345007, or see its linkset.

How it's tested

This resolver was run against GS1's own official resolver conformance suite and passes. That is a technical test of the resolver, not a certification of the company, and QR Code 42 is not affiliated with or endorsed by GS1.

Hosted or self-hosted

GS1 also publishes an open-source community-edition resolver (GS1 Resolver CE) that you can run yourself. QR Code 42 is the hosted option: you claim your GTINs and publish links in a dashboard or through the API, and we run the resolver, keep it fast, and export the labels.