What Is Supplemental Feed?
Also written as supplemental data source, sub feed, secondary feed.
Definition
A supplemental feed is a second data source in Merchant Center that overlays fields on your primary product feed, matched by id. For an ecommerce store, this is how you change titles, labels or categories for Google Ads without editing the live store product. The primary feed still owns price and stock.
Written by Christopher Krassnig, Founder & CEO of ZenoX Media. Written by the ZenoX team from the accounts we run. Definitions are general; the numbers in examples are maths, not client results.
Supplemental Feed, Explained
The primary feed is the source of truth for what exists: id, price, availability, image, link. A supplemental feed is a thinner file. It lists the same id and only the fields you want to override or add. Merchant Center joins the two on id. Google then sees one product with the combined attributes.
The common mistake is uploading a second primary feed with the same products. That can create duplicate offers and disapprovals. Another mistake is putting price or stock in the supplemental file, then watching it fight the store sync. Price should stay in the primary feed so the live page and Google cannot drift.
Use the supplemental feed for titles, custom labels, product type, category and extra detail fields. Keep one id per product, matching the primary feed exactly. After it lands, open a product in Merchant Center and confirm the overlay actually stuck. If a campaign filters on a label that never arrived, the listing group will be empty.
How We Use It at ZenoX
We ship title rewrites, custom labels and category fixes through a supplemental feed, never by editing Shopify as the source of truth. That is how Hyperfeed lands on 200+ ecom accounts. The Labelizer writes champion, potential, sleeper and waster values into the same overlay. Campaigns then filter on those labels.
Questions People Ask About Supplemental Feed
What Is a Supplemental Feed in Merchant Center?
It is a second data source that sits on top of your primary product feed. You match rows by id and only send the fields you want to change or add, such as title or custom labels. Merchant Center merges the two. Google still sees one product, not two.
Can I Use a Supplemental Feed Instead of Changing Shopify Titles?
Yes. That is the usual reason to use one. Keep price, stock, image and link in the primary store feed. Put the Google-facing title, labels and category in the supplemental file. Do not upload the same products as a second primary feed. Two primary feeds with the same id can clash.
Related terms
- Product FeedA product feed is the data file that tells Google Merchant Center what you sell, item by item.
- Custom LabelA custom label is a free-text field on your product feed that you fill with values you choose, such as margin tier or performance bucket.
- Merchant CenterMerchant Center is Google's catalog tool that holds your product feed and checks each item against Shopping rules.
- Product Title OptimizationProduct title optimization is rewriting Shopping titles so they match the words buyers actually type.
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