Regex GLN (Global Location Number)

A GLN (GS1 Global Location Number) is thirteen digits whose last digit is a check digit computed with the same alternating 1/3 weighting as EAN-13 and GTIN-14 (see related pages) — and it has the exact same length: thirteen digits. The consequence is blunt: a regex cannot tell a GLN apart from an EAN-13, a GTIN-13, or any other thirteen-digit GS1 key; only context (which field, which system) or a GS1 registry lookup can. It's the cleanest illustration on this site of the core idea — a regex validates a SHAPE, never an identity. Unlike an EAN-13, which identifies a product, a GLN identifies a legal entity, a function, or a physical location: it's used as a trading-partner identifier in EDI and e-invoicing (Peppol, France's Chorus Pro, EDIFACT). Telling fact: python-stdnum, a well-maintained Python library with 200+ real-world identifier validators, ships an ean.py module but no gln.py — because a GLN has, structurally, nothing extra to validate beyond what an EAN-13 already needs. Can you verify a GLN actually exists? Not with a regex: you'd need to query the GS1 registry, which means being a GS1 member or using a service like Verified by GS1 — a regex, even a perfect one, says nothing about whether the number is real.