To make your product reviews to your products, Google will use GTIN and metadata information such as SKU, Brand + MPN pairs, and product URLs. To do this, you need to:
- Use GTIN as a strong identifier across your product feed and your product reviews feed. To do this, you have to upload the GTIN in the barcode field in the Shopify Products dashboard.
- Use SKU as the value of the ID in the product reviews feed. Judge.me will do it for you using the information you provide in the Shopify Products Admin. Learn more about this requirement in Google's official documentation.
- Create a product feed with SKU as item id. For an app to create a product feed with SKU as item id (instead of a Shopify Product ID as item id), we recommend these two apps: Feed for Google Shopping and ShoppingFeeder.
- Shopify's Google Shopping app does not allow you to use SKU as item id in your products feed. You can only use the Shopify Product ID.
- If you change the product ID in your product feed inside your Google Merchant Center account, you will lose the product's advertising history in Merchant Center and AdWords. Please study Google's documentation for product ids for further details.