## Summary

Some product data, like price and availability, naturally changes over time.
You need to maintain your product feed regularly to keep this information
up-to-date.

You can use supplemental feeds and the [Products API](https://developers.google.com/shopping-content/guides/products/products-api) to update product
data. Supplemental feeds can only be created in the
[Merchant Center UI](https://merchants.google.com), and they must be linked to a primary
feed.

## Manual steps

To maintain your inventory with supplemental feeds, see [Create a supplemental
feed](https://support.google.com/merchants/answer/7439058#supplemental).

You can also use [automatic item updates](https://support.google.com/merchants/answer/3246284) to keep
price and availability information up-to-date. Merchant Center can use embedded
structured data from your website to update products if the price or
availability differs from the information currently stored in the Merchant Center.

Automatic item updates are designed to fix small problems with product
price and availability, not to be the main method of updating product data. You
should use them in addition to supplemental feeds and the Content API.

To enable automatic item updates, follow the steps in
[About automatic item updates](https://support.google.com/merchants/answer/3246284).

## Automatic steps

To update information product information with the Content API for Shopping,
use the [Products API](https://developers.google.com/shopping-content/guides/products/products-api).

You can use the [`insert`](https://developers.google.com/shopping-content/guides/products/products-api#productsinsert) and [`update`](https://developers.google.com/shopping-content/guides/products/products-api#productsupdate) methods to create and update
individual items.

Like product inserts and updates, multiple inventory updates can be batched into
a single Content API for Shopping call using the [`products.custombatch`](https://developers.google.com/shopping-content/reference/rest/v2.1/products/custombatch) method.