Hi @fredbra,
Thank you for reaching out and for the clarification. I understand that issues like this can be both confusing and frustrating, especially when you’re managing a large catalog of products.
To clarify, Google requires valid GTINs (Global Trade Item Numbers) that match its database of registered manufacturer codes such as UPC, EAN, JAN, or ISBN. Since your internal codes are not part of that registry, Google automatically flags them as invalid and displays the message “This value is not valid [gtin].”
If you don’t have valid GTINs, an approach you can try though not recommended is brand+MPN. First you’ll need to remove the GTIN attribute entirely and instead provide two identifiers: your Brand name and an MPN (Manufacturer Part Number). You can use your internal product code as the MPN. Google recognizes the combination of Brand and MPN as a valid alternative to GTIN, ensuring your products remain eligible for listing.
For the Google for WooCommerce plugin (the official integration), here’s what you should do. Go to Marketing → Google for WooCommerce → Attributes. Unmap or remove the GTIN field or its mapping. It’s also a good idea to bulk-edit your products in WooCommerce to clear any existing GTIN values you’ve entered.
Next, make sure your internal product code is entered in the SKU field at the product level. Then, map this SKU field to MPN in the Google attributes section. Finally, create brand entries for your products if you haven’t already, assign each product a brand, and then resync your product feed.
To clarify, providing brand and MPN is strongly recommended, especially for branded products, as it helps Google identify and match products accurately. However, products without a GTIN are at a disadvantage, and performance may be limited because Google prioritizes products that have them.
