Item Group ID [item_group_id] Field for Product Feed

Required for product variants in specific contexts (Google & ChatGPT)

The item_group_id attribute links product variants together so they are shown as a group to shoppers. Variants differ only by attributes such as size, color, material, pattern, age_group, or gender.

When to use

• Required for free listings when submitting product variants.
• Required for Shopping ads with variants in:
  • Brazil
  • France
  • Germany
  • Japan
  • United Kingdom
  • United States
• Not required for single, standalone products with no variants.

Format

• Type: String (alphanumeric, underscores, dashes; ASCII recommended)
• Limits: 1–50 characters
• Repeated field: No
• Schema.org properties:
  • Product.inProductGroupWithID
  • ProductGroup.productGroupId

File format examples:

Minimum requirements

• Use the same value for all variants of the same product.
• Each distinct variant group must have a unique item_group_id.
• Include at least one variant attribute (color, size, material, pattern, age_group, gender).
• Ensure all products in the same group have values for the same variant attributes.
• Do not use item_group_id for unrelated products.
• Do not rely on casing differences to make IDs unique.
• Do not reuse item_group_id values for unrelated product groups.

Best practices

• Use the parent SKU as the item_group_id for all variants in a group.
• Do not submit the parent SKU as a separate product.
• Keep the value stable over time to maintain consistent grouping.
• Ensure each variant has a unique id value while sharing the same item_group_id.
• Provide different landing page URLs for each variant (e.g., /t-shirt/green or /t-shirt?color=green&size=small).

SEO Tip

Correctly grouping variants improves the shopping experience by letting users browse color, size, or material options from a single product page. This can increase click-through rates and reduce the number of duplicate-looking listings.

Official Source : https://support.google.com/merchants/answer/6324507