GTIN hygiene: the least glamorous, highest-leverage fix
Bad barcodes quietly break product matching everywhere. How to find invalid GTINs in your catalog and what to do when a product genuinely has none.
Why GTINs matter to agents
A GTIN (the number under the barcode — UPC, EAN, ISBN) is the closest thing commerce has to a universal product key. Surfaces use it to match your listing against known products, aggregate reviews, and trust your data. A missing or invalid GTIN downgrades your product from 'a known thing' to 'a string of text'.
The failure modes we see
Invalid check digits from typos or spreadsheet mangling (Excel loves turning barcodes into scientific notation), the same GTIN pasted across every variant, placeholder values like 0000000000000, and SKUs entered where GTINs belong. All of these are machine-detectable — a GTIN's last digit is a checksum, so validation is exact, not heuristic.
When you genuinely have no GTIN
Handmade, custom, and own-brand products often have no barcode, and that's fine: the specs allow identifier-less products if you say so explicitly and provide brand plus MPN where applicable. What hurts is inventing values — wrong data is worse than absent data, because it breaks matching silently.
ShelfReady's audit validates every GTIN's checksum, flags duplicates and placeholders, and tells you which products can legitimately ship without one.