Each product in your Google Shopping feed needs a unique ID to distinguish it from other stock keeping units (SKUs). Google uses this ID to identify and track product performance across different channels. This attribute is mandatory for every product in your shopping feed. 

It is advisable to use SKUs as product IDs. SKUs provide structure to your landing pages and help prevent duplicate IDs across different products. 

Universal product identifiers like the Global Trade Item Number (GTIN) and manufacturer part number (MPN) affect performance on Google shopping campaigns. This does not apply to product ID. Shoppers will not see the product ID on shopping results. But you want the product ID to appear in your structured data and shopping feeds.

How To Use The Product ID Attribute

To ensure Google understands your product ID, follow these guidelines:

  • Use valid Unicode characters, preferably ASCII-only, which includes alphanumeric letters, underscores, and dashes.
  • The ID should be 1 to 50 characters long.
  • Provide a unique ID for each product and SKU in your feed. Don’t reuse or recycle the same ID for different products. Reused IDs will cause inaccurate advertising and conversion data.
  • Maintain a consistent ID for each product and use the same ID for a product across different countries
  •  Use a unique combination of letters and numbers. Don’t create different product IDs like AAO579 and aaO579 where the only difference is capitalization.
  • Use different IDs for each product variant.

Product Variants and Item Group ID

To differentiate between variants, assign a unique ID to each variant based on the parent SKU. First, you have to use the [item_group_id] attribute to group variants. 

Consider a situation where you have a parent SKU for a set of three variants of the same product. Use the parent SKU as the value for the [item_group_id]  attribute. Then you will create three unique product IDs for each variant.  Derive these IDs from the parent SKU that you set in the [item_group_id]. 

For example, maybe you sell a specific size 11 shoe in blue, green, and red. The item group ID might be something like 12345S-11. The product IDs can be 12345S-11-R for red shoes, 12345S-11-B for the blue variant, and 12345S-11-G for the green shoes.

Again, always make sure each SKU in your shopping feed has a unique SKU ID.

Conclusion

Just like you have a unique identification number such as GTIN and MPN, each product and SKU in your Google Shopping feed needs a unique ID. This ID is what Google uses to identify a product. While we use product IDs to get product data, titles can boost conversion rates, and here’s a post about them.