What to check first
- Open the affected Shopify product and inspect every variant, not just the parent product.
- Confirm the barcode field contains a real manufacturer GTIN, UPC, EAN, or ISBN.
- Do not fill missing barcodes with SKU values, internal IDs, or made-up numbers.
- Confirm brand or vendor is present and consistent.
- Check whether Merchant Center receives the final GTIN value or only Shopify stores it.
When no GTIN exists
If the product is custom, private label, handmade, vintage, or otherwise does not have a manufacturer GTIN, the feed may need the right combination of brand, MPN, and identifier_exists. The safe setup depends on the product type and what identifiers truly exist.
Fast diagnosis method
- Export your Shopify product CSV.
- Filter rows where barcode or GTIN is blank.
- Filter rows where barcode equals SKU or looks too short.
- Compare those rows to Merchant Center diagnostics.
- Fix repeated identifier patterns at the feed source before editing items one by one.
Want to scan the feed first?
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