What is a GTIN in a multi-brand feed?
WeAdU · Updated 19 October 2026
A GTIN (Global Trade Item Number) is the trade item number assigned by the manufacturer: UPC, EAN, JAN or ISBN. In a multi-brand feed, the gtin attribute receives that number and not the store's own code: submit it only when it is certain, and do not guess it.
Where does the GTIN go when several brands share one feed?
The row id is the merchant's offer. It can belong to the store. The GTIN, the brand and the MPN come from the manufacturer. Several brands fit in one file: each row keeps the GTIN of its item, not a code shared by the catalogue. When the GTIN and the variant attributes are the same, one offer is expected per country and per language. The same item, sold by another merchant, carries the same codes.
The Merchant Center specification requires the GTIN when the merchant knows it. The attribute page recommends it. If the manufacturer never assigned one, the field stays empty. Send the brand and the MPN instead. Do not put a SKU there, or a code invented for the listing. With no manufacturer code at all, send neither gtin, nor brand, nor mpn. A GTIN that exists but is missing, or a GTIN that is wrong, can limit the product's visibility or get the product disapproved.
What does identifier_exists do?
The identifier_exists attribute is optional. Its default is yes. The value no is for media with no GTIN, apparel with no brand, or, in other cases, an item with no GTIN and no MPN tied to a brand. With no, send the codes you actually have. A product that has codes, submitted as no, receives a warning. Do not use it to hide a number you have not checked.
Which value for a variant, a bundle or a compatible?
Each colour or each size has its own GTIN. Do not reuse the GTIN of a neighbouring variant. A bundle built by the manufacturer takes the bundle's GTIN. A bundle built by the store takes the GTIN of the main product. A manufacturer multipack takes the multipack's GTIN. A multipack assembled by the store takes the item's GTIN. A third-party compatible carries that third party's GTIN, not the original manufacturer's. If no GTIN was assigned, the attribute stays empty.
What does the WeAdU audit cover?
All our audits cover Google Ads only. This page defines the number. It does not promise serving, and it does not promise that a disapproval will be avoided. The help pages cited below were read on 2 October 2026.
Help pages
Google help pages read on 2 October 2026.