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.
58,612 users
Redux DevTools
DevTools for Redux with actions history, undo and replay.
52,872 users
Allow Right-Click
Re-enable the possibility to use the context menu on sites that overrides it
47,235 users
Nimbus Screen Capture: Screenshot, Edit, Annotate
★ Used by Several Million users on different platforms ★ 1) Screen capture web pages 2) Selected regions 3) Whole browser window 4) Slack upload Edit screenshots. Save images as local files or Google Drive. Tools for Annotation. Upload and share
44,373 users
Selenium IDE
Selenium IDE is an integrated development environment for Selenium tests. It is implemented as a Firefox extension, and allows you to record, edit, and debug tests.
40,108 users
WhatFont
A wrapper for Chengyin Liu's WhatFont tool
36,000 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.
35,976 users
Proxy SwitchyOmega
Manage and switch between multiple proxies quickly & easily.
35,520 users
JavaScript-Java Bridge
A replacement for the Java Plugin so Java Applets without graphics continue to work on browsers that no longer support NPAPI plugins. Java's LiveConnect API is emulated — data & method calls can be exchanged, and Java can manipulate the webpage DOM.
33,005 users
Stylish - Custom themes for any website
Stylish lets you customize any website with custom user styles (themes for websites). Choose from the largest userstyles library to change the color scheme, background, and skin for Google, Facebook, YouTube and many, many more sites.
31,273 users
Disable WebRTC
WebRTC leaks your actual IP addresses from behind your VPN, by default.
28,009 users
CORS Everywhere
A firefox addon allowing the user to enable CORS everywhere by altering http responses. Report issues to the repository, with enough information to reproduce the problem: https://github.com/spenibus/cors-everywhere-firefox-addon/issues
24,230 users
Colorpick Eyedropper
A simple eye-dropper & color-picker tool allowing you to select color values from webpages. You will need to enable the add-on bar Firefox menu->Options->Add-on Bar OR View->Toolbars->Add-on Bar Then refresh the page.
23,010 users
SAML-tracer
A tool for viewing SAML and WS-Federation messages sent through the browser during single sign-on and single logout.
22,659 users
JSONView
View JSON documents in the browser.
22,602 users
Media Converter and Muxer - Audio Tools
Easy to use video and audio converter and muxer written in WebExtension built on top of the well-known FFmpeg converter
22,511 users
User-Agent Switcher
Quickly and easily switch between popular user-agent strings.
22,036 users
WAVE Accessibility Extension
Evaluate web accessibility within the Firefox browser. When activated, the WAVE extension injects icons and indicators into your page to give feedback about accessibility and to facilitate manual evaluation.
21,673 users
Font Finder (revived)
An easy-to-use font inspector to get CSS styles of the selected element
21,529 users
ImageAssistant Batch Image Downloader
An image extractor for sniffing, analyzing and batch downloading images from web page.
21,426 users
cookies.txt
Exports all cookies to a Netscape HTTP Cookie File, as used by curl, wget, and youtube-dl, among others.
19,872 users
Xdebug Helper for Firefox
This extension is very useful for PHP developers that are using PHP tools with Xdebug support like PHPStorm, Eclipse with PDT, Netbeans and MacGDBp or any other Xdebug compatible profiling tool like KCacheGrind, WinCacheGrind or Webgrind.
19,700 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)
17,417 users
SeoQuake SEO extension
Accelerate your SEO efforts on the fly. SEOquake is a free plugin for browsers that provides you with key SEO metrics for a specific page, along with other useful tools such as SEO Audit and many others.
17,236 users
Lightning Autofill
The most popular autofill extension, boosting productivity since 2010.
16,658 users