Google Merchant Centre Supplemental Feeds: Override Data Without Touching Your Main Feed

What supplemental feeds do

A supplemental feed is a secondary data source that maps to your primary feed by item ID. It can override or add attributes without touching the primary feed. This is useful when the primary feed comes from your ecommerce platform (Shopify, WooCommerce, Magento) and you cannot easily modify the output.

Common uses for supplemental feeds

The most common use cases are: adding custom labels for campaign segmentation, overriding generic product titles with SEO-optimised versions, adding missing GTINs, overriding availability for items that are out of stock faster than the primary feed updates, and adding promotion IDs to flag items for a merchant promotion.

• Custom labels: tag by margin tier, seasonality or bestseller status
• Title overrides: add brand, material, colour, size to front-load the title
• Availability overrides: set to 'out of stock' for items pending restock

Setting up a supplemental feed

In Merchant Centre, go to Products > Feeds > Add supplemental feed. Choose Google Sheets for ease of maintenance or a CSV for automated exports. Map the feed to your primary feed using the id column. Only include the item IDs and attributes you want to override — you do not need to replicate the full primary feed.

Key takeaways

• Supplemental feeds override specific attributes without touching your primary data source.
• Custom labels for campaign segmentation are the most common supplemental feed use case.
• Map supplemental feeds using the id column — include only the items and attributes you want to change.

Frequently asked questions

What is a Google Merchant Centre data feed?

A data feed is a file that contains all your product information: titles, descriptions, prices, images, availability and more. Google uses this feed to display your products in Shopping ads and free listings.

Where is TPR Media based?

TPR Media operates from Level 34, 1 Eagle Street, Brisbane City QLD 4000, serving clients across Brisbane and Australia-wide.

TPR Media explains Merchant Centre supplemental feeds: how to override product titles, add custom labels and fix attributes for Australian retailers without modifying the primary Shopify, WooCommerce or Magento feed.