per ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/developer)
    15. [ devtools_page ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/devtools_page)
    16. [ dictionaries ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/dictionaries)
    17. [ externally_connectable ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/externally_connectable)
    18. [ homepage_url ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/homepage_url)
    19. [ host_permissions ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/host_permissions)
    20. [ icons ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/icons)
    21. [ incognito ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/incognito)
    22. [ manifest_version ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/manifest_version)
    23. [ name ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/name)
    24. [ offline_enabled ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/offline_enabled)
    25. [ omnibox ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/omnibox)
    26. [ optional_permissions ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/optional_permissions)
    27. [ options_page ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/options_page)
    28. [ options_ui ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/options_ui)
    29. [ page_action ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/page_action)
    30. [ permissions ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/permissions)
    31. [ protocol_handlers ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/protocol_handlers)
    32. [ short_name ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/short_name)
    33. [ sidebar_action ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/sidebar_action)
    34. [ storage ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/storage)
    35. [ theme ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme)
    36. [ theme_experiment ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/theme_experiment)
    37. [ user_scripts ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/user_scripts)
    38. [ version ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/version)
    39. [ version_name ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/version_name)
    40. [ web_accessible_resources ](/en-US/docs/Mozilla/Add-ons/WebExtensions/manifest.json/web_accessible_resources)
  8. Extension Workshop 
    1. [ Develop ](https://extensionworkshop.com/documentation/develop/)
    2. [ Publish ](https://extensionworkshop.com/documentation/publish/)
    3. [ Manage ](https://extensionworkshop.com/documentation/manage/)
    4. [ Enterprise ](https://extensionworkshop.com/documentation/enterprise/)
  9. [ **Contact us** ](/en-US/docs/Mozilla/Add-ons/Contact_us)
  10. Channels 
    1. [ Add-ons blog ](https://blog.mozilla.org/addons)
    2. [ Add-ons forum ](https://discourse.mozilla.org/c/add-ons)
    3. [ Add-ons chat ](https://chat.mozilla.org/#/room/%23addons:mozilla.org)

##  In this article

  * Key resources 
  * Get started 
  * Concepts 
  * User interface 
  * How to 
  * Firefox workflow 
  * Reference 

#  Browser extensions

Extensions, or add-ons, can modify and enhance the capability of a browser.
Extensions for Firefox are built using the WebExtensions API cross-browser
technology.

The technology for extensions in Firefox is, to a large extent, compatible
with the [ extension API
](https://developer.chrome.com/docs/extensions/reference/) supported by
Chromium-based browsers (such as Google Chrome, Microsoft Edge, Opera,
Vivaldi). In most cases, extensions written for Chromium-based browsers run in
Firefox with [ just a few changes
](https://extensionworkshop.com/documentation/develop/porting-a-google-chrome-
extension/) .

##  Key resources

Guides

    

Whether you're just beginnin