optional_permissions

Type Array
Mandatory No
Manifest version 2 or higher
Example
json
"optional_permissions": [
  "webRequest"
]

Use the optional_permissions key to list permissions you want to ask for at runtime, after your extension has been installed.

The permissions key lists permissions that your extension needs before it can be installed. In contrast, optional_permissions lists permissions that your extension doesn't need at install time but can ask for after installation. To ask for a permission, use the permissions.request() API. Asking for a permission presents the user with a dialog requesting them to grant the permission to your extension, unless all the permissions requested are granted silently.

For advice on designing your request for runtime permissions, to maximize the likelihood that users grant them, see Request permissions at runtime.

Note: Users can manage optional permissions from the Firefox Add-ons Manager. Extensions that use optional permissions can check for the permissions granted by the user with permissions.getAll() and listen for permissions.onAdded and permissions.onRemoved to know when a user grants or revokes permissions.

The key can contain host permissions and API permissions.

Host permissions

These are the same as the host permissions you can specify in the permissions key.

Note: When using Manifest V3 or higher, optional host permissions should be specified using the optional_host_permissions manifest key. Firefox introduced optional_host_permissions in release 128, see bug 1766026, and allows the continued use of optional_permissions to specify optional hosts. Use of optional_host_permissions, however, is recommended.

API permissions

The optional API permissions are:

  • activeTab
  • background
  • bookmarks
  • browserSettings
  • browsingData
  • clipboardRead
  • clipboardWrite
  • contentSettings
  • contextMenus
  • cookies
  • debugger
  • declarativeNetRequest
  • declarativeNetRequestFeedback
  • declarativeNetRequestWithHostAccess
  • devtools
  • downloads
  • downloads.open
  • find
  • geolocation
  • history
  • idle
  • management
  • nativeMessaging
  • notifications
  • pageCapture
  • pkcs11
  • privacy
  • proxy
  • scripting
  • search
  • sessions
  • tabHide
  • tabGroups
  • tabs
  • topSites
  • userScripts (optional-only)
  • webNavigation
  • webRequest
  • webRequestBlocking
  • webRequestFilterResponse
  • webRequestFilterResponse.serviceWorkerScript

Check the compatibility table for browser-specific support details.

These optional permissions are granted silently, without a user prompt:

  • activeTab
  • cookies
  • idle
  • tabGroups
  • webRequest
  • webRequestBlocking
  • webRequestFilterResponse
  • webRequestFilterResponse.serviceWorkerScript

Optional-only permissions

Optional permissions are generally available for use in the permissions key, so they can be requested at install time. However, some browsers support the concept of optional-only permissions, permissions that can only be requested at runtime. For example, in Firefox, optional-only permissions can be granted by the user from the extension's options page or using permissions.request(). Optional-only permissions must be requested individually and alone through the permissions.request() API.

The optional-only API permissions are:

Examples

json
 "optional_permissions": ["*://developer.mozilla.org/*"]

In Manifest V2 only, enable the extension to ask for privileged access to pages under developer.mozilla.org.

json
  "optional_permissions": ["tabs"]

Enable the extension to ask for access to the privileged pieces of the tabs API.

json
  "optional_permissions": ["*://developer.mozilla.org/*", "tabs"]

In Manifest V2 only, enable the extension to ask for both of the above permissions.

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Firefox for Android
Safari on iOS
optional_permissions
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
activeTab
Chrome – Full support
Chrome 26 (Release date: 2013-03-26)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
alarms
Chrome – Full support
Chrome 22 (Release date: 2012-09-25)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
background
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
bookmarks
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
browserSettings
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 57 (Release date: 2017-11-14)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 57 (Release date: 2017-11-28)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
browsingData
Chrome – Full support
Chrome 19 (Release date: 2012-05-15)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 77 (Release date: 2020-06-02)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
clipboardRead
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
clipboardWrite
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
contentSettings
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
contextMenus
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote
footnote Available as an alias to the menus permission.
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote
footnote Available as an alias to the menus permission.
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote
footnote Available as an alias to the menus permission.
Safari on iOS – No support
Safari on iOS
footnote No support
cookies
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
declarativeNetRequest
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – No support
Firefox
footnote No support
Opera – No support
Opera
footnote No support
Safari – Full support
Safari 15 (Release date: 2021-09-20)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
declarativeNetRequestFeedback
Chrome – Full support
Chrome 84 (Release date: 2020-07-27)
footnote
footnote Available only to unpacked extensions.
Edge – Full support
Edge 84 (Release date: 2020-07-16)
footnote
footnote Available only to unpacked extensions.
Firefox – Full support
Firefox 113 (Release date: 2023-05-09)
footnote Full support
Opera – Full support
Opera 70 (Release date: 2020-07-27)
footnote
footnote Available only to unpacked extensions.
Safari – Full support
Safari 15.4 (Release date: 2022-03-14)
footnote Full support
Firefox for Android – Full support
Firefox for Android 113 (Release date: 2023-05-09)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15.4 (Release date: 2022-03-14)
footnote Full support
declarativeNetRequestWithHostAccess
Chrome – Full support
Chrome 96 (Release date: 2021-11-15)
footnote Full support
Edge – Full support
Edge 96 (Release date: 2021-11-19)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 82 (Release date: 2021-12-02)
footnote Full support
Safari – Full support
Safari 16 (Release date: 2022-09-12)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – Full support
Safari on iOS 16 (Release date: 2022-09-12)
footnote Full support
devtools
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 77 (Release date: 2020-06-02)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
dns
Chrome – Preview support
Chrome Canary
footnote
footnote The dns API is only available in Chrome Dev.
footnote Preview browser support
Edge – No support
Edge
footnote No support
Firefox – No support
Firefox
footnote No support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
downloads
Chrome – Full support
Chrome 31 (Release date: 2013-11-12)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 60 (Release date: 2018-05-09)
footnote Full support
Opera – Full support
Opera 18 (Release date: 2013-11-19)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 60 (Release date: 2018-05-09)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
downloads.open
Chrome – Full support
Chrome 31 (Release date: 2013-11-12)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 60 (Release date: 2018-05-09)
footnote Full support
Opera – Full support
Opera 18 (Release date: 2013-11-19)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 60 (Release date: 2018-05-09)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
find
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 57 (Release date: 2017-11-14)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
geolocation
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
history
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
identity
Chrome – Full support
Chrome 29 (Release date: 2013-08-20)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 16 (Release date: 2013-08-27)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
idle
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
management
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 77 (Release date: 2020-06-02)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
menus
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
altname
altname Alternate name: contextMenus
Opera – No support
Opera
footnote No support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
altname
altname Alternate name: contextMenus
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
nativeMessaging
Chrome – Full support
Chrome 29 (Release date: 2013-08-20)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 87 (Release date: 2021-03-23)
footnote Full support
Opera – Full support
Opera 16 (Release date: 2013-08-27)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
notifications
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
pageCapture
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
pkcs11
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 77 (Release date: 2020-06-02)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
privacy
Chrome – Full support
Chrome 19 (Release date: 2012-05-15)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 75 (Release date: 2020-04-07)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
proxy
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 77 (Release date: 2020-06-02)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
scripting
Chrome – Full support
Chrome 88 (Release date: 2021-01-19)
footnote
footnote Available for use in Manifest V3 or later.
Edge – Full support
Edge 88 (Release date: 2021-01-21)
footnote
footnote Available for use in Manifest V3 or later.
Firefox – Full support
Firefox 102 (Release date: 2022-06-28)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – Full support
Safari 15.4 (Release date: 2022-03-14)
footnote Full support
Firefox for Android – Full support
Firefox for Android 102 (Release date: 2022-06-28)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15.4 (Release date: 2022-03-14)
footnote Full support
search
Chrome – Full support
Chrome 87 (Release date: 2020-11-17)
footnote Full support
Edge – Full support
Edge 87 (Release date: 2020-11-19)
footnote Full support
Firefox – Full support
Firefox 63 (Release date: 2018-10-23)
footnote Full support
Opera – Full support
Opera 73 (Release date: 2020-12-09)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 63 (Release date: 2018-10-23)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
sessions
Chrome – Full support
Chrome 37 (Release date: 2014-08-26)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 77 (Release date: 2020-06-02)
footnote Full support
Opera – Full support
Opera 24 (Release date: 2014-09-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
storage
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
tabGroups
Chrome – Full support
Chrome 89 (Release date: 2021-03-02)
footnote Full support
Edge – Full support
Edge 89 (Release date: 2021-03-04)
footnote Full support
Firefox – Full support
Firefox 139 (Release date: 2025-05-27)
footnote Full support
Opera – Full support
Opera 75 (Release date: 2021-03-24)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 139 (Release date: 2025-05-27)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
tabHide
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 61 (Release date: 2018-06-26)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
tabs
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
topSites
Chrome – Full support
Chrome 19 (Release date: 2012-05-15)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android 55 – 68 (Release date: 2017-08-08)
footnote Removed in 79 and later
Safari on iOS – No support
Safari on iOS
footnote No support
unlimitedStorage
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Partial support
Safari 14 – 15.6 (Release date: 2020-09-16)
footnote Partial support
footnote Grants a 10 MB storage quota, instead of the standard 5 MB.
Safari – Full support
Safari 16 (Release date: 2022-09-12)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – Partial support
Safari on iOS 15 – 15.6 (Release date: 2021-09-20)
footnote Partial support
footnote Grants a 10 MB storage quota, instead of the standard 5 MB.
Safari on iOS – Full support
Safari on iOS 16 (Release date: 2022-09-12)
footnote Full support
userScripts
Chrome – Full support
Chrome 120 (Release date: 2023-12-05)
footnote Full support
Edge – Full support
Edge 120 (Release date: 2023-12-07)
footnote Full support
Firefox – Full support
Firefox 136 (Release date: 2025-03-04)
footnote
footnote Provided as an optional-only permission.
Opera – Full support
Opera 106 (Release date: 2023-12-19)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – No support
Firefox for Android
footnote No support
Safari on iOS – No support
Safari on iOS
footnote No support
webNavigation
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 15 (Release date: 2021-09-20)
footnote Full support
webRequest
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – Full support
Safari 14 (Release date: 2020-09-16)
footnote Full support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – Full support
Safari on iOS 18 (Release date: 2024-09-16)
footnote Full support
webRequestBlocking
Chrome – Full support
Chrome 18 (Release date: 2012-03-28)
footnote Full support
Edge – Full support
Edge 79 (Release date: 2020-01-15)
footnote Full support
Firefox – Full support
Firefox 55 (Release date: 2017-08-08)
footnote Full support
Opera – Full support
Opera 15 (Release date: 2013-07-02)
footnote Full support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 55 (Release date: 2017-08-08)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
webRequestFilterResponse
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 110 (Release date: 2023-02-14)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 110 (Release date: 2023-02-14)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
webRequestFilterResponse.serviceWorkerScript
Chrome – No support
Chrome
footnote No support
Edge – No support
Edge
footnote No support
Firefox – Full support
Firefox 95 (Release date: 2021-12-07)
footnote Full support
Opera – No support
Opera
footnote No support
Safari – No support
Safari
footnote No support
Firefox for Android – Full support
Firefox for Android 95 (Release date: 2021-12-07)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
Partial support
Partial support
In development. Supported in a pre-release version.
In development. Supported in a pre-release version.
No support
No support
See implementation notes.
Uses a non-standard name
Has more compatibility info.