Glossary · Feeds & Merchant Center
What is a supplemental data source?
A supplemental data source — often called a supplemental feed — is a file or sheet that adds or overrides attributes on products that already exist in Merchant Center. It is matched to products by ID and cannot create or delete products. It is the standard way to send categories without editing your store.
What this comes down to
- It cannot add or remove products, and cannot be used on its own.
- Rows match on
idexactly, plus the feed label and language. - The tab only appears once the “Advanced data source management” add-on is on.
- The Bulk Mapper’s
supplemental-feed.csvis shaped for exactly this upload.
What it can and cannot do
Google’s documentation is direct: a supplemental data source can’t be used to add or remove products or as a standalone data source. What it does is fill in attributes that are missing from the primary source, or change ones that are there — titles, custom labels, product types, GTINs and similar.
Each row must match a product’s ID exactly. The source is also tied to a feed label and a language, which must match the primary data too.
Setting one up
The Supplemental sources tab is hidden until you enable the “Advanced data source management” add-on under Settings → Add-ons. If you cannot find the tab, this is why.
- In Merchant Center, turn on the Advanced data source management add-on.
- Go to Settings → Data sources and open the Supplemental sources tab.
- Add supplemental product data and choose a file, Google Sheets or API.
- Enter the file name, the Product ID column, the data source label and the language.
- Link it to the primary data source it applies to, then create it.
The full walkthrough, including checking the result, is in override Google’s automatic category with a supplemental feed.
Questions
Can a supplemental feed change google_product_category?
Google describes supplemental sources as supplying attributes missing from, or overriding those in, the primary source, and google_product_category is an optional attribute. Google’s own value is still used unless your value falls in one of the cases where Google accepts an override.
What columns does it need?
An id column matching your products exactly, plus a column per attribute you are supplying — for categories, google_product_category.
Sources
Read next
- Primary data sourceThe Merchant Center data source that defines which products exist and supplies their core attributes; supplemental sources can only modify products it contains.
- Product ID (id)The required feed attribute that uniquely identifies a product in Merchant Center, and the key that supplemental data sources match on exactly.
- Advanced data source managementA Merchant Center add-on, enabled under Settings → Add-ons, that makes the Supplemental sources tab and its options available.
- How to override Google's automatic product category with a supplemental feedWhat a supplemental feed can and cannot change, when Google accepts a category override, and the exact two columns to submit in the file.