When you enable product reviews in the app settings, we send the barcodes from your Shopify products to Google along with each survey opt-in. Google uses these barcodes, specifically GTINs (Global Trade Item Numbers), to match reviews to individual products, which can contribute to Google Product Ratings appearing alongside your products in Shopping ads and free listings.
For this to work, your products need to have valid GTINs entered in Shopify's Barcode field.
What counts as a valid GTIN?
A GTIN is a standardised numeric identifier assigned to a product. You'll most commonly encounter them as:
UPC (12 digits) — standard in North America
EAN (13 digits) — standard in Europe and most other regions
ISBN (13 digits) — used for books
These are usually printed on your product packaging as the number beneath or above the barcode. If you resell products from a manufacturer, the GTIN should be available from them or printed on the packaging. If you manufacture your own products, you can obtain GTINs through GS1, the organisation that issues them globally.
Not every product has a GTIN. Handmade, custom, vintage, or one-of-a-kind items typically don't have one, and that's fine. The product reviews feature will simply skip any products in the order that don't have a barcode set.
For more detail on GTIN formats and validation, see Google's documentation: GTIN [gtin] attribute.
Where to add barcodes in Shopify
Shopify stores GTINs in the Barcode (ISBN, UPC, GTIN, etc.) field, which you'll find in the inventory section of each product or variant.
For products without variants, the barcode field appears directly on the product detail page. For products with variants, each variant has its own barcode field — you'll need to enter the GTIN for each variant individually, since different sizes or colours will typically have different GTINs.
If you have a large catalogue, Shopify's built-in bulk editor lets you update barcodes across many products at once. You can also import barcodes via CSV.
For full instructions, see Shopify's help documentation:
Product details - covers the barcode field and where to find it
Adding and updating products - includes bulk editing and CSV import
How Google uses the barcodes we send
When a customer opts in to the Google survey through our app, we include the GTINs from the products in their order. Google then uses these identifiers to associate the resulting review with specific products in its catalogue.
For product-level reviews to appear in Google Shopping, your products also need to be listed in Google Merchant Center with matching GTINs. Google matches reviews to products based on these identifiers, so the GTIN in Shopify, your Merchant Center product feed, and the physical product packaging should all be consistent.
For more on how Google's Product Ratings programme works and its requirements, see:
Product Ratings basics - overview of the programme
Product Ratings eligibility - requirements for ratings to appear on your ads
What if my products don't have GTINs?
If your products don't have GTINs, for example, if you sell custom or handmade goods, you can still use the app for store-level google customer reviews.
Simply leave the product reviews toggle disabled in your survey opt-in settings. Google will still collect feedback about the overall shopping experience, which contributes to your store's seller rating.