Most Popular Extensions

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Adblock Plus No Restart Featured

Blocks annoying video ads on YouTube, Facebook ads, banners and much more.

Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).

Rated 5 out of 5 stars (4,801)
20,965,371 users

Video DownloadHelper No Restart

The easy way to download and convert Web videos from hundreds of YouTube-like sites.

Rated 4 out of 5 stars (6,385)
4,527,530 users

NoScript Security Suite Featured

The best security you can get in a web browser!
Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.

Rated 5 out of 5 stars (1,568)
2,263,491 users

Easy Screenshot

Capture a screenshot of the whole webpage, and save in your desktop in default.

Rated 4 out of 5 stars (84)
2,228,264 users

Firebug No Restart

Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page...

Rated 5 out of 5 stars (1,828)
2,180,026 users

Ghostery No Restart Featured

Enjoy a faster, safer and cleaner browsing experience.

Rated 4 out of 5 stars (1,296)
1,498,255 users

DownThemAll! Featured

The first and only download manager/accelerator built inside Firefox!

Rated 4 out of 5 stars (1,724)
1,318,699 users

Greasemonkey Featured

Customize the way a web page displays or behaves, by using small bits of JavaScript.

Rated 4 out of 5 stars (983)
1,291,149 users

Adblock Plus Pop-up Addon Featured

Adblock Plus Pop-up Addon extends the blocking functionality of Adblock Plus to those annoying pop-up windows that open on mouse clicks and other user actions.

Rated 5 out of 5 stars (193)
1,153,483 users

Flash Video Downloader - YouTube HD Download [4K]

Flash Video Downloader helps you download any video (flv, mp4, HD) from YouTube, Facebook, Break, Metacafe and more in one click. You can download mp3, music (iPod), avi and more. Download Flash games. Download Helper. 4K download.

Rated 4 out of 5 stars (598)
1,086,758 users

Download YouTube Videos as MP4 No Restart Featured

An extension that adds direct links to download YouTube videos as MP4 and FLV. It has a simple interface and it downloads videos directly from YouTube. The extension integrates with YouTube's interface and adds a download button below the player.

Rated 4 out of 5 stars (400)
1,082,722 users

uBlock Origin No Restart Featured

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

Rated 5 out of 5 stars (474)
1,019,868 users

Yahoo Toolbar

Stay on top of the information you care about with the Yahoo Toolbar. Preview your favorite sites, like Facebook, Gmail, eBay and more, from any page you’re on.

Rated 2 out of 5 stars (395)
989,262 users

Web of Trust, WOT: Website Reputation Ratings Featured

Find out which websites you can trust. WOT adds intuitive traffic light-style icons next to search results and URLs so you can decide whether to visit a site:
• Green – The site is trusted
• Yellow – Be cautious
• Red – Online threats detected

Rated 4 out of 5 stars (1,445)
964,197 users

FlashGot Mass Downloader Featured

Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.

Rated 5 out of 5 stars (524)
857,131 users

Tab Mix Plus Featured

Tab Mix Plus enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more. It also includes a full-featured session manager.

Rated 4 out of 5 stars (2,588)
848,085 users

Google Translator for Firefox Featured

With this addon you can translate any text to your own language with one click or hot-key. You can either translate the selected text, this way the translated text will overwrite the original selected text, or you can translate the full page too.

Rated 4 out of 5 stars (333)
803,891 users

LastPass Password Manager

LastPass, an award-winning password manager, saves your passwords and gives you secure access from every computer and mobile device.

Rated 4 out of 5 stars (1,337)
758,340 users

YouTube Video and Audio Downloader No Restart

Downloads YouTube videos in all available formats (FLV, MP4, WebM, and 3GP) with video quality of your choice. It also contains a pure JavaScript library to extract the ORIGINAL audio file embedded in video files.

Rated 4 out of 5 stars (317)
735,624 users

Test Pilot

DEPRECATED: The Test Pilot program has been dormant for years, but things are beginning to stir. Don't bother installing this add-on, it's old and busted, but keep an eye out for new developments soon!

Rated 4 out of 5 stars (71)
730,631 users