Missing GTIN

Microsoft requires GTINs to match products against its catalog. Missing GTINs result in disapproval, identical to Google's policy.

Same root causes as Google's missing GTIN: empty field, wrong field used, or a private-label product without a real GTIN.

1. Add the GTIN to the gtin attribute. Microsoft accepts UPC, EAN, ISBN, and JAN.
2. If no GTIN exists, set identifier_exists to FALSE and supply both brand and mpn.
3. Validate check digits before submission.

• Using SKUs as GTINs
• Stripped leading zeros in spreadsheets