Merchant Center Identifiers
Missing GTIN, or a GTIN that already exists
A real barcode, or an honest blank. Never a guessed one.
GTIN is the barcode the manufacturer assigned: UPC, EAN, JAN or ISBN. Google says to submit it when the product has one, and not to guess. If you are the only seller of a product with no barcode, you generally omit it and set identifier_exists honestly. “GTIN already exists” means that code is already on another offer.
Missing
Look at the packaging, not at a neighboring listing. Each variant needs its own GTIN. A store brand or a custom bundle often has no GTIN. Leaving the field empty is correct. Filling it with zeros, a coupon prefix, or another brand’s code gets the item disapproved.
Already exists
- The same variant was submitted twice, with two ids.
- A color or size reused the parent barcode.
- You copied a supplier row and did not change the code.
For compatible products, Google says to use the GTIN and brand of the manufacturer who built the item you sell, not the original brand you are compatible with.
Questions people ask
Can I buy a GS1 barcode to clear the error?
Only if it identifies the product you sell. A fresh code on someone else’s product does not make the identifier true.
What about identifier_exists?
Set it to match reality. False means you do not have a GTIN. True with an empty GTIN is a contradiction.
Do digital products need one?
Google’s GTIN help says non-physical items need a GTIN too when one is assigned. The same code can cover a digital edition of the same product.
Google’s own pages