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Selenium IDE Requires Restart

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.

Rated 4 out of 5 stars (25)
123,499 users

Screengrab (fix version) Requires Restart

Screengrab! saves webpages as images.
0.99 released!
New features: upload to internet

Rated 5 out of 5 stars (250)
120,404 users

MeasureIt Requires Restart

Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.

Rated 4 out of 5 stars (362)
119,993 users

Simple YouTube to MP3/MP4 Converter and Downloader Compatible with Firefox 57+

Download youtube videos as mp3/mp4/ogg/webm fast and easy! Adding mirrors everyday to decrease any downtime! We monitor comments and work to fix any problems as soon as possible!

Rated 4 out of 5 stars (169)
119,900 users

Print Edit Requires Restart Featured

Allows editing of web page content while in Print Preview mode, prior to printing or saving as HTML or PDF. Compacts the layout and removes unwanted content such as adverts, sidebars and blank pages. Any element can be formatted, hidden or deleted.

Rated 5 out of 5 stars (294)
119,824 users

Emoji Keyboard Compatible with Firefox 57+ Featured

A free extension of the web tool https://emojikeyboard.org. It helps input emoji in the web browser with an extensive search functionality.

Rated 4 out of 5 stars (67)
118,589 users

Empty Cache Button Requires Restart

Cache clearing made easy. One click.

Rated 4 out of 5 stars (87)
116,189 users

Modify Headers Requires Restart

Add, modify and filter the HTTP request headers sent to web servers. This addon is particularly useful for Mobile web development, HTTP testing and privacy.

Rated 4 out of 5 stars (78)
114,378 users

Strict Pop-up Blocker

Quickly toggle between blocking all pop-up windows and allowing some pop-ups

Rated 4 out of 5 stars (103)
113,921 users

Youtube Downloader 4K - Video Downloader Requires Restart

Download from YouTube 4K videos and thousands other video websites.

Rated 4 out of 5 stars (416)
113,362 users

Youtube MP3 Podcaster Requires Restart

Self contained add-on for downloading youtube videos to mp3 for easy listening on podcasting gadgets like a Zune or iPod

Rated 4 out of 5 stars (227)
110,959 users

Theme Font & Size Changer Featured

Theme Font & Size Changer lets you change the global font size and font family used for the user interface in Firefox. Design your browser with your favorite font.

Rated 5 out of 5 stars (170)
110,637 users

Доступ к Рутрекеру

Не знаешь как зайти на Рутрекер? Установи и пользуйся!

Rated 4 out of 5 stars (60)
110,607 users

YouTube ALL HTML5

Play all videos on YouTube with your preferred settings (size, quality, playback rate, …) without cookies using only HTML5.

Rated 4 out of 5 stars (143)
110,535 users

Text Link Requires Restart

Allows URI texts written in webpages to be loaded by double clicks.

Rated 4 out of 5 stars (285)
110,139 users

Menu Wizard Requires Restart Featured

Customize menus : Helps removing, moving and renaming menus and menu items
Colorize important menu for ease of use! (use Style (CSS))
Change or disable any of used keyboard shortcuts
Support: Firefox, Thunderbird and SeaMonkey

Rated 5 out of 5 stars (187)
109,406 users

JSONView

View JSON documents in the browser.

Rated 5 out of 5 stars (177)
109,144 users

JavaScript Debugger Requires Restart

As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.

Venkman is the code name for Mozilla's JavaScript Debugger. Venkman aimed to provide a powerful JavaScript debugging environment for Mozilla based browsers.

Rated 4 out of 5 stars (50)
107,752 users

Youtube and more – Easy Video Downloader

Download and save videos playing on a website like youtube to your hard disk

Rated 4 out of 5 stars (410)
107,736 users

R-kiosk Requires Restart

Real Kiosk is a Firefox extension that defaults to full screen, disables all menus, toolbars, key commands and right button menus. Alt+Home still takes you home. ...

Rated 4 out of 5 stars (111)
107,210 users