Content API in Merchant Center
The Content API for Shopping allows apps to interact directly with the Merchant Center platform, vastly increasing the efficiency of managing large or complex Merchant Center accounts. The Content API for Shopping can be used as an input source for product data in Merchant Center, directly delivering your data as it is updated on your site.
Note: If you plan to upload a large number of feeds or make frequent changes to your product data, it is strongly recommended that you use the Content API (instead of feeds) to directly upload your product data.
If you choose to submit your product data through the Content API and there isn't an input feed already in place, a feed will automatically be created in Merchant Center. This new primary feed allows you to create custom feed rules for your API data and manage your feed within the Merchant Center product. Alternatively, you can create a placeholder feed for your Content API and upload the API product data to the placeholder feed.
Submitting to multiple countries
Due to the nature of the Content API, items will not be replicated for multiple countries within a single feed. If you want to submit your Content API product data to multiple countries, you must create multiple input feeds with the new target countries and languages.
Supplemental API feeds
You may use supplemental feeds to upload product data through the Content API. You'll need to create your supplemental feed in Merchant Center and use the feed ID for Content API requests. The ID can be found on the 'Feeds' page under the 'Settings' section of your registered supplemental Content API feed.
Unlike primary feeds, you may have multiple supplemental Content API feeds. You may choose to do this, for example, if you have one database for availability and one database for price. You'll be able to update the price separately from the availability – and therefore register a unique supplemental feed for price and availability.