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storage

Enables WebExtensions to store and retrieve data, and listen for changes to stored items.

The storage system is based on the Web Storage API, with a few differences.

To use this API you need to include the "storage" permission in your manifest.json file. Each WebExtension has its own storage area, which can be split into different types of storage.

Types

storage.StorageArea
An object representing a storage area.
storage.StorageChange
An object representing a change to a storage area.

Properties

storage has three properties, which represent the different types of available storage area.

storage.sync
Represents the sync storage area. Items in sync storage are synced by the browser, and are available across all instances of that browser that the user is logged into, across different devices.
storage.local
Represents the local storage area. Items in local storage are local to the machine the extension was installed on.
storage.managed
Represents the managed storage area. Items in managed storage are set by the domain administrator and are read-only for the extension. Trying to modify this namespace results in an error.

Events

storage.onChanged
Fired when one or more items change in a storage area.

Browser compatibility

Chrome Edge Firefox Firefox for Android Opera
StorageArea Yes Yes 45.0 48.0 33
StorageArea.clear Yes Yes 45.0 48.0 33
StorageArea.get Yes Yes 45.0 48.0 33
StorageArea.getBytesInUse Yes Yes 45.0 48.0 33
StorageArea.remove Yes Yes 45.0 48.0 33
StorageArea.set Yes Yes * 45.0 48.0 33
StorageChange Yes Yes 45.0 48.0 33
local Yes Yes 45.0 * 48.0 33
managed Yes No No No No
onChanged Yes Yes 45.0 48.0 33
sync Yes No No No No

Chrome incompatibilities

  • Firefox does not support:
    • managed storage area
    • sync storage area
    • getBytesInUse().

Example add-ons

Acknowledgements

This API is based on Chromium's chrome.storage API. This documentation is derived from storage.json in the Chromium code.

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

Document Tags and Contributors

 Contributors to this page: wbamberg, chrisdavidmills
 Last updated by: wbamberg,