Most Popular Extensions

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JSONView

View JSON documents in the browser.

Rated 5 out of 5 stars (164)
116,343 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 (234)
116,197 users

Bluhell Firewall Featured

Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.

Rated 5 out of 5 stars (287)
113,766 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)
112,633 users

Toolbar Buttons Featured

Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.

Rated 4 out of 5 stars (324)
112,083 users

Fast Dial Requires Restart

Visual bookmarks for Firefox.

Rated 3 out of 5 stars (2,519)
112,024 users

ipFlood Requires Restart

Simulate the use of a series of proxy changing at each new connection.

Rated 5 out of 5 stars (31)
110,841 users

Tree Style Tab Requires Restart

Show tabs like a tree.

Rated 4 out of 5 stars (1,358)
110,162 users

Thumbnail Zoom Plus Requires Restart Featured

Shows full image when you hover over a thumbnail. Works with Amazon, Baidu Images, Bing Images, Facebook, Flickr, Google+, Google Images, IMDb, LinkedIn, Netflix, Pinterest, Reddit, Twitter, Yandex, YouTube, Wikipedia, Yahoo Images, & many more.

Rated 4 out of 5 stars (359)
108,869 users

The Addon Bar (Restored)

Gives you a place to put all your add-on buttons without over-crowding the navigation bar.

Rated 5 out of 5 stars (333)
108,736 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 (74)
108,654 users

FEBE Requires Restart

FEBE (Firefox Environment Backup Extension) allows you to quickly and easily backup your Firefox extensions. In fact, it goes beyond just backing up -- It will actually rebuild your extensions individually into installable .xpi files.

Rated 4 out of 5 stars (661)
108,477 users

Webmail Ad Blocker Featured

Expand your email area by blocking and removing ads on the right hand side of the screen when using Gmail, Hotmail, Outlook.com and Yahoo Mail.

Rated 4 out of 5 stars (198)
107,656 users

Simple YouTube to MP3/MP4 Converter and Downloader

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 5 out of 5 stars (35)
107,267 users

Tamper Data Requires Restart Featured

Use tamperdata to view and modify HTTP/HTTPS headers and post parameters...

Rated 4 out of 5 stars (139)
106,818 users

TinEye Reverse Image Search Requires Restart

TinEye is a reverse image search engine. The plugin adds a context menu item that allows you to search for an image to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions.

Rated 4 out of 5 stars (186)
106,183 users

Cookies Manager+ Requires Restart

Cookies manager to view, edit and create new cookies. It also shows extra information about cookies, allows edit multiple cookies at once and backup/restore them.

Rated 5 out of 5 stars (65)
104,463 users

CLIQZ- search directly in your browser

CLIQZ integrates an innovative quick search engine into Firefox. Spare yourself the detour via search engine pages. With privacy enhancements such as anti-tracking, CLIQZ gives you control over your data.

Rated 4 out of 5 stars (51)
104,352 users

Tab Groups Featured

Tab Groups are an easy way to organize a lot of tabs. You can visually group related tabs, switch between groups, and quickly search through all of your tabs to switch to a specific one.

Rated 5 out of 5 stars (482)
103,589 users

Grammarly for Firefox

Grammarly’s free spelling and grammar checker ensures that everything you type is easy to read, effective, and mistake-free. As you type, Grammarly underlines spelling mistakes and grammatical errors and helps you fix them on the fly.

Rated 3 out of 5 stars (41)
100,537 users