Firefox Add-on

Firefox Add-ons are cross-platform extensions built on the WebExtensions API to customize browser functionality and privacy.

Developers use the standard WebExtensions API (compatible with Chrome and Edge) to build Firefox Add-ons using HTML, CSS, and JavaScript. These tools integrate directly with the browser UI via the manifest.json file to manage tabs, block content, or modify network requests. Mozilla’s ecosystem prioritizes security through mandatory code signing and a rigorous review process. With over 30,000 extensions available, including industry standards like uBlock Origin and Bitwarden, the platform offers deep integration into the Gecko rendering engine for granular user control.

https://addons.mozilla.org