Attribute rules
Attribute rules are Merchant Center settings that change your product data before Google uses it, for example by taking the title from a supplemental feed.
How it works
Merchant Center builds each product from one primary feed and any supplemental feeds. A default rule combines them in the order you set. Custom rules, the ones you write yourself, go further: they can change an attribute or create a new one from existing data. Our guide to Merchant Center feed rules has recipes for common fixes.
Rules run each time Merchant Center processes your data, so a feed upload and an API update pass through the same rules. The result is the processed product: the version Merchant Center shows and can use in ads and listings. The data you submitted stays as it was.
Where you see it
- Merchant Center: in the settings of a product data source, where you create and manage custom rules.
- Merchant API: the Data Sources sub-API handles the default rules that link supplemental sources to a primary one, but not complex custom rules.
Example
Example store, not client data.
The tableware shop’s feed has titles like “Dinner plate 27 cm” and a separate color column. A rule on the title adds the colour from that column, so the processed title reads “Dinner plate 27 cm white”. One rule covers all 3,000 products, and the feed file itself stays as it was.
Not to be confused with
- Supplemental feed — a separate data source that brings new values for products already in the primary feed. A rule can only change data that one of your sources already holds.
- Automatic item updates — Google corrects the price, availability and condition to match your product pages. Rules are your own instructions and never read the site.
Right and wrong readings
- Wrong: “A rule can label products by how well they sell.” Right: a rule works only with what your data sources contain. Sales per product are reported in Google Ads, so a sales-based label has to arrive as data, for example as a column in a supplemental feed.
Sources
- Make frequent updates to your products — how rules combine primary and supplemental data, when they apply, the processed product. Checked 2 October 2026.
- Manage various data source types — the default rule and the order of sources; what the Merchant API supports for rules. Checked 2 October 2026.
- Manage API data sources for product uploads — custom rules are managed in the Merchant Center interface. Checked 2 October 2026.