Most Popular Extensions


User Agent Switcher

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

Rated 4 out of 5 stars (251)
349,497 users

Easy Youtube Video Downloader Express No Restart

Only one with 1080p Full-HD and 192kbps MP3 Direct Links. A clean, fast and simple addon for superfast and easy downloads in FLV,3GP,MP3,MP4,720p, 1080p qualities on Youtube pages.

Rated 4 out of 5 stars (685)
337,727 users

S3.Google Translator

S3.Google Translator adds the power of Google Translate’s automatic translations to your browser!
It supports translation of selected text, entered phrase or whole webpage between any of 80+ languages.

New Feature: Language learning!

Rated 5 out of 5 stars (255)
324,875 users


Adds some tools to import and export folders and messages

Rated 4 out of 5 stars (127)
310,137 users

Xmarks Sync

Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!

Rated 4 out of 5 stars (2,526)
305,535 users

Provider for Google Calendar

Allows bidirectional access to Google Calendar

Rated 4 out of 5 stars (1,034)
295,769 users

FoxyProxy Standard

FoxyProxy is an advanced proxy management tool that completely replaces Firefox's limited proxying capabilities. For a simpler tool and less advanced configuration options, please use FoxyProxy Basic.

Rated 4 out of 5 stars (346)
289,761 users

Session Manager No Restart

Session Manager saves and restores the state of all or some windows - either when you want it or automatically at startup and after crashes. It can also automatically save the state of open windows individually.

Rated 5 out of 5 stars (435)
280,396 users Downloader (music/videos/photos @ VK)

Download music, videos and photos from / One-click download, natural filenames, displaying file size and bitrate for music, downloading HD video, downloading HQ photos. No spam, no usage of your account, no spyware.

Rated 5 out of 5 stars (424)
277,141 users

YouTube Flash Video Player No Restart

YouTube Flash Video Player is a powerful tool that will let you choose Flash video player as default YouTube video player.

Rated 5 out of 5 stars (37)
275,105 users


Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...

Rated 5 out of 5 stars (306)
273,170 users

YouTube High Definition No Restart

YouTube High Definition is a powerful tool that will let you automatically play all YouTube videos in HD (High Definition), turn off annotations, change video player size, auto stop videos, auto mute videos, control embedded videos and much more.

Rated 5 out of 5 stars (209)
271,647 users


This add-on is a downloader that lets you easily download videos from sites like Youtube, Facebook, Metacafe, Dailymotion, Break, VKontakte and music for example from SoundCloud, Grooveshark and from many other sites...

Rated 4 out of 5 stars (365)
262,923 users

Full Web Page Screenshots (♥♥♥♥♥)

FireShot makes full web page screenshots. Demo:

Screenshots can be quickly captured and:

― Saved as Image or PDF
― Sent to clipboard
― Printed
― Annotated *
― Uploaded *
― E-Mailed *

* OS Windows only

Rated 5 out of 5 stars (439)
253,860 users

Download Status Bar No Restart

If you are the kind of person who likes to have total control over every aspect of your downloads, "Download Status Bar" is the add-on you are looking for.

Rated 5 out of 5 stars (339)
243,700 users

µBlock No Restart

Finally, an efficient blocker. Easy on CPU and memory.

Rated 4 out of 5 stars (215)
230,275 users

MinimizeToTray revived

Minimizes windows into the system tray.

Rated 4 out of 5 stars (313)
228,699 users


The most beautiful yet the simplest add-on that makes a strong colorful appeal. Colors every tab in a different color and makes them easy to distinguish while beautifying the overall appearance of the interface. For Seamonkey & Flock. An essential. F...

Rated 4 out of 5 stars (995)
219,045 users

SQLite Manager

Manage any SQLite database on your computer.

Rated 5 out of 5 stars (40)
192,270 users


LookOut is a plugin which allows Thunderbird to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).

Rated 4 out of 5 stars (147)
181,371 users