Supplemental feeds are additional data feeds in Google Merchant Center that allow you to enhance or update existing product data without replacing your primary feed.
They do not create new products. Instead, they add or modify attributes of products that already exist in your main feed — based on a shared identifier (usually the Item ID).
Common use cases
- Adding custom labels for campaign structuring
- Updating promotional text or seasonal messaging
- Overwriting titles or descriptions for optimization
- Adding missing attributes without changing your core feed
Why it matters
Supplemental feeds provide flexibility. They allow marketing teams to optimize product data for performance without needing developer access to the primary product feed.
In short: Supplemental feeds enhance your main product feed and give you more control over optimization and segmentation.