Dark Reader
Dark mode for every website. Take care of your eyes, use dark theme for night and daily browsing.
1,172,259 users
Ghostery – Privacy Ad Blocker
Ghostery is a powerful privacy extension. Block ads, stop trackers and speed up websites.
1,045,789 users
FoxyProxy Standard
FoxyProxy is an open-source, advanced proxy management tool that completely replaces Firefox's limited proxying capabilities. No paid accounts are necessary; bring your own proxies or buy from any vendor. The original proxy tool, since 2006.
215,487 users
Stylus
Redesign your favorite websites with Stylus, an actively developed and community driven userstyles manager. Easily install custom themes from popular online repositories, or create, edit, and manage your own personalized CSS stylesheets.
111,420 users
Tampermonkey
Tampermonkey is the world's most popular userscript manager.
710,476 users
ColorZilla
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
153,488 users
User-Agent Switcher
Easily override the browser's User-Agent string
66,472 users
Cookie-Editor
Cookie-Editor lets you efficiently create, edit and delete a cookie for the current tab. Perfect for developing, quickly testing or even manually managing your cookies for your privacy.
65,346 users
Cookie Quick Manager
An addon to manage cookies (view, search, create, edit, remove, backup, restore, protect from deletion and much more). Firefox 57+ is supported.
64,194 users
Ruffle - Flash Emulator
Putting Flash back on the web. Designed to be easy to use, this extension will seamlessly enable you to play flash content, with no extra configuration required!
51,143 users
Allow Right-Click
Re-enable the possibility to use the context menu on sites that overrides it
42,230 users
Disable JavaScript
Adds the ability to disable JavaScript for specific sites or specific tabs. You can customize the default JS state (on or off), the disable behavior (by domain or by tab) and much more.
37,367 users
WhatFont
A wrapper for Chengyin Liu's WhatFont tool
35,818 users
RESTClient, a debugger for RESTful web services.
RESTClient has been completely rewritten for compatible with Firefox 57. Some functions are still missing (OAuth & OAuth 2.0 authentication).
34,651 users
Disable WebRTC
WebRTC leaks your actual IP addresses from behind your VPN, by default.
29,599 users
Google Lighthouse
Lighthouse is an open-source, automated tool for improving the performance, quality, and correctness of your web apps.
16,936 users
cookies.txt
Exports all cookies to a Netscape HTTP Cookie File, as used by curl, wget, and youtube-dl, among others.
16,469 users
RESTED
A REST client for the rest of us
15,990 users
JSON Lite
Fast JSON viewer - highlights, shows items count/size, handles large files
15,052 users
JavaScript Toggle On and Off (WebExtension)
Toggle JavaScript engine on and off the easy way
14,826 users
My IP Hider VPN
My IP Hider VPN is number one tool for hiding your IP and unblocking any web site! If your Firefox version is less then 55 please install older My IP Hider VPN from "Version History" (https://goo.gl/7ZQQjZ)
14,308 users
Empty Cache Button
Cache clearing made easy. One click.
13,609 users
Fake Filler
A form filler that fills all form inputs (textboxes, textareas, radio buttons, dropdowns, etc.) with fake and randomly generated data. The purpose of this extension is to help developers and testers test forms quickly and easily.
12,178 users
Emoji Cheatsheet
A reference for the codes to generate Emojis on popular sites like GitHub or Basecamp and Unicode characters for Twitter and Facebook. Search Emojis by name or view recently selected items. Emojis are automatically copied to the clipboard.
11,302 users
Proxy Toggle
Toggle between direct connection and a single proxy server via a toolbar icon.
11,277 users