- Every sellable item has its own GTIN, and no GTIN is reused for a different item.
- The GTIN appears on the product page in text or structured data, not only on the physical barcode.
- The MPN is published where you have one, and it matches what retailers use.
- Variants that differ in a way a buyer cares about — size, capacity, region — have their own GTIN.
- The variant attribute is stated in words next to its identifier.
- Retail partners receive the same identifiers in their feeds; mismatches between your page and theirs are listed and fixed.
- Every product has one canonical URL, and that URL appears in your structured data and feeds.
- Superseded identifiers stay on record against the old product, not deleted.
ChecklistUpdated 2026-09-21
Product identifier checklist
Use it once per catalogue, then on every new product. Identifiers are what let a model tell that a manufacturer page, a retailer listing and a review describe the same item; without them it matches by name, and names drift.