How to fix: Duplicate identifier

Multiple products share the same identifier values; each offer must have a unique identifier set.

Product identifiers (GTIN, MPN, brand) anchor Google's matching of your product to its catalog. Issues here typically come from non-numeric characters in GTIN, mismatched UPC vs EAN length, brand-GTIN ownership conflicts in GS1's database, or duplicate GTINs across multiple SKUs.

1. Verify the GTIN ownership using GS1 GEPIR — confirms which brand legitimately owns the code (https://gepir.gs1.org).
2. Strip all non-numeric characters from GTIN values: no dashes, no letters, no spaces.
3. UPC = 12 digits, EAN-13 = 13 digits, ISBN-13 = 13 digits starting with 978/979.
4. If the product is private-label without a real GTIN, request a GTIN exemption rather than fabricating one.
5. Re-upload your corrected feed; new identifiers take 24–72 hours to propagate.

• Buying GTINs from non-GS1 resellers — they map to defunct brands and trigger validation failures
• Reusing the same GTIN across multipack and single-unit variants — Google flags duplicates