In order to upload your product data in Google Merchant Center, you will first need to create a feed to which you can submit your data. This step is required for any new feed and, once a feed is registered, you can update the existing feed without having to register it again.
Primary feeds
A primary feed is the required data source that Merchant Center uses to display your products on Google. If the product data in your primary feed already meets our product data specification and policies, creating and submitting a primary feed is the only feed action you will need to take. Product data that does not meet the Merchant Center requirements can be adapted by using the advanced feed features, including supplemental feeds. In addition, you can use supplemental feeds to enhance or override your product data to improve the performance of your ads.
Use primary feeds to add or remove product data, set language and country targeting, and set feed rules for your product data. Primary feeds are the only feed type that can add or remove products.
Google recommends submitting all of your products in a single feed for all programmes. For newly created feeds, all applicable feed destinations can be selected during feed creation. If you have existing feeds that you want to opt into an additional destination, such as local inventory ads or free listings, you can do so via primary feed settings. If you need to exclude products from one of your chosen destinations, you may use the excluded_destination attribute.
If you have a legacy product feed created before 3 October 2019, this does not apply to you and you can continue to submit offers eligible for Shopping ads and local inventory ads in separate feeds.
in the primary feed section to create a new primary feed. Follow the prompts and provide the following information about your data:- Country of sale: The country of sale is the main country in which products from this feed are sold. Product data in this feed must meet the requirements for the country that you submit, including the feed specifications and policies. You can add additional countries for Shopping ads when you select destinations during the feed creation process.
- Language: The language in which your product data is written. Learn more about using the right language and currency
- Destination: Choose one or many feed destinations in Merchant Center to allow you to determine which Google programmes can use the items in your data feed. Learn more about multiple destinations
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Add multiple countries (Shopping ads and free listings): Click Add multiple countries to specify additional countries in which you'd like to show your products. Note that your country of sale will remain the default country for products included in the feed. You may only add available countries for the given language of the feed, and may want to consider which countries will be most relevant for the language. Learn more about showing products in multiple countries of sale
- Primary feed name: Enter a descriptive name that helps you identify the primary feed. The feed name doesn't need to match the name of the file that you're submitting.
- Input method: Select the one that best fits your needs:
- Google Sheets: You can upload your data using a generated Google Sheets template, or with an existing Google Sheet with your product data. Learn more about Google Sheets
- Scheduled fetch: Google can fetch your feed directly from your server.
- Upload: Upload files directly to Merchant Center via SFTP, FTP, Google Cloud Storage or manually.
- Website crawl: If there are no feeds currently in your account and you have the appropriate structured data on your website, Google can crawl your website to retrieve your product data. Learn more
- File name: Depending on which input method you select, you may be prompted to enter the name of the file that you'll be submitting. This name should exactly match the name of the file that you created and include a valid extension.
After you have provided the information and clicked Continue, you can view and manage your newly created primary feed in the 'Feeds' section of your Merchant Center account.
To manually fetch or upload a feed, click on the three-dot icon 
Add an additional country of sale (Advanced)
Adding an additional country of sale lets you use the same primary feed to show your product data to multiple countries, carrying over the same feed rules and updates for all countries. You can also apply different feed rules or Shopping campaigns to countries that share the same primary feed.
To add an additional country of sale, click on the three-dot icon
Supplemental feeds
Supplemental feeds provide additional, or supplemental, data that can be connected to existing product data in the primary feed. Supplemental feeds cannot add or remove products or be used as a standalone feed; instead, they're used to update existing product data. Supplemental feeds can provide additional information to multiple primary feeds.
To use a supplemental feed, connect it to an existing primary feed through the id attribute. Supplemental feeds will only update your product data when the supplemental feed contains IDs that already exist in a primary feed.
id attributes for supplemental feeds match exactly with the id attributes for primary feeds as they are case sensitive.Legacy online inventory update feeds
If you want to use a separate feed for pricing and availability updates, you can do this by creating a supplemental feed and using the 'Take latest' rule to update your primary feed.
How it works
When creating a supplemental feed, you'll change your selection to indicate that you'd like to join your feeds with the id [id] attribute.
For example:
Primary feed:
| id [id] | title [title] | price [price] | brand [brand] |
|---|---|---|---|
| 1 | shirt | 34 | Brand A |
| 2 | shoes | 55 |
Brand B |
| 3 | hiking boots | 100 | Brand C |
| 4 | trousers | 75 | Brand A |
Supplemental feed that uses the id [id] attribute to match to the primary feed:
| id [id] | custom_label [custom_label] |
|---|---|
| 1 | SALE |
| 4 | SALE |
Resulting feed:
| id [id] | title [title] | price [price] | brand [brand] | custom_label [custom_label] |
|---|---|---|---|---|
| 1 | shirt | 34 | Brand A | SALE |
| 2 | shoes | 55 | Brand B | |
| 3 | hiking boots | 100 | Brand C | |
| 4 | trousers | 75 | Brand A | SALE |
A supplemental feed is a secondary data source used to provide additional attributes, both required and optional, that may be missing from your primary feed. Supplemental feeds cannot be used as a main data source. Common use cases for supplemental feeds include, but are not limited to:
- Add or override custom labels for campaign management
- Add or override promotion IDs for retail promotions
- Override titles
- Exclude specific products (via the
excluded_destinationattribute) - Add missing GTINs
- Add local inventory product data for local inventory ads
- Add or override country-specific attributes for a primary feed with multiple countries of sale
Each supplemental feed must have an id [id] attribute column, along with at least one additional column with the data that you would like to connect to a primary feed.
To create a supplemental feed, go to the Feeds section under the Products page in Merchant Center. At the top of the supplemental feeds table, click on Add a supplemental feed to create a new supplemental feed. Follow the prompts and provide the following pieces of information about your data:
- Supplemental feed name: Enter a descriptive name that helps you to identify the supplemental feed. The supplemental feed name doesn't need to match the name of the file that you're submitting.
- Input method: Select the one that best fits your needs:
- Google Sheets: You can upload your data using a generated Google Sheets template, or with an existing Google Sheet with your product data. Learn more about Google Sheets
- Scheduled fetch: Google can fetch your feed directly from your server.
- Upload: Upload files directly to Merchant Center via SFTP, FTP, Google Cloud Storage or manually.
- File name: Depending on which input method you select, you may be prompted to enter the name of the file that you'll be submitting. This name should exactly match the name of the file that you created and include a valid extension.
- Linking to primary feed: Select any primary feed and country of sale/language combination to which the supplemental feed belongs.
- Fetch schedule: Set a scheduled fetch for your product data. This lets Merchant Center get fresh feeds without you needing to manually upload your data.
To manually upload or fetch a feed, click on the three-dot icon 
Once your supplemental feed has been created and linked to a primary feed, Merchant Center will automatically create a rule, which you can find in the 'feed rules' section of Merchant Center. The rule will connect the product data from the two feeds based on the id value provided, and will connect attribute data from the supplemental feed.
