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 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.
Note: If you have ideas or questions or need help, you can reach us on the community forum or in the Add-ons Room on Matrix.
Discover what extensions can do before building your first extension. Learn about the anatomy of an extension and get an overview of the extension development and publication workflow, Firefox style. Explore a little deeper with a comprehensive selection of example extensions that you can run right in Firefox.
Discover all the user interface components you can use in your extensions, with coding examples and tips.
From patterns you’ll regularly use such as work with the Tabs API and adding a button to the toolbar to more advanced topics such as intercepting HTTP requests and working with contextual identities, you’ll find a range of tutorials to get you started.
When you are ready to create your extension for Firefox or port your Chrome extension head over to Extension Workshop. It has details on:
Get full details about the manifest keys, including all their properties and settings. There’s also detailed information on the compatibility of each key with the major browsers.
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