GS1 Digital Link parser

Paste a GS1 Digital Link URI or scan text from a barcode reader to see its Application Identifiers, canonical form, and the raw element string.

Canonical form

Element string: what the till sees

• Empty input

Redirect chain

Where does this link actually take a shopper? Follow redirects sends just the URL to our server, which walks the chain hop by hop and reports each step's status, key headers and timing. Everything else on this page stays in your browser.

About Application Identifiers

Every piece of data in a GS1 barcode — a GTIN, a batch number, a serial number, an expiry date — is tagged with an Application Identifier, or AI: a two-to-four digit prefix that says what the value that follows means. AIs are what let a single barcode carry several distinct facts without ambiguity, and what let a resolver or a till read a stream of digits and know exactly where one field ends and the next begins.

The most important AI is 01, the GTIN — the primary key that says what the product is, always 14 digits, zero-padded if the product started life with a shorter GTIN-8, UPC-A or EAN-13. Everything else narrows that identity further. AI 10, batch or lot number, groups units made together — useful for recalls and traceability, shared by every item in the same production run. AI 21, serial number, is the opposite: unique to one physical item, used when you need to tell two units of the same product apart, such as for warranty tracking or anti-counterfeiting. A GS1 Digital Link URI carries these as path segments — /01/{gtin}, /10/{lot}, /21/{serial} — in a fixed order, plus data attributes like expiry (AI 17) as query parameters.

A barcode itself doesn't have slashes and query strings — that's only how a Digital Link URI encodes the data for the web. The element string above is closer to what a scanner actually reads off the code: fixed-length AIs like the GTIN need no delimiter, because the reader always knows exactly how many digits follow. Variable-length fields like lot and serial can end anywhere, so each one (except the last) is terminated by FNC1 — the barcode symbol that separates fields — which decodes to an ASCII Group Separator (GS, 0x1D) once the scanner passes the data on. That GS character is invisible in normal text, which is exactly the point: it's a machine delimiter, not something a person is meant to read.

This matters because point-of-sale systems never contact a server to ring up a sale. A till reads the element string straight off the barcode and parses it by AI, offline, the same way it has read GS1-128 barcodes for decades — the web-resolvable Digital Link URI only comes into play when a phone camera or browser opens the link instead of a laser scanner reading it. Both views of the same data, path-and-query URI and delimited element string, describe the same set of AIs; this tool shows you both from the same input.

Building a Digital Link from scratch instead of parsing one? Try the Digital Link builder.