Unique Product Identifiers Requirements for Google Shopping

Unique Product Identifiers (UPI) uniquely distinguish products you are selling and help users search for your products online. Product manufacturers assign the UPI's to each product. Common UPI's include Global Trade Item Numbers (GTINs), Manufacturer Part Numbers (MPNs), and brand names. Not all products have UPI's and, if more than one seller sells a specific product, the UPI's will be identical. When you provide your product data, you'll provide different identifiers depending on the product type. Google recommends always submitting all three attributes (GTIN, brand, and MPN) for better ad performance and to improve search results. Some products, such as customized products, don’t have a GTIN assigned or even a brand, so you don’t need to submit one. Be aware that when Google knows that there is a GTIN for your product (a manufacturer or other merchant has supplied GTINs for the same product) they will require that you add it correctly.