Most Popular Extensions
View JSON documents in the browser.
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
Bluhell Firewall Featured
Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
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.
Fast Dial Requires Restart
Visual bookmarks for Firefox.
ipFlood Requires Restart
Simulate the use of a series of proxy changing at each new connection.
Tree Style Tab Requires Restart
Show tabs like a tree.
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.
Gives you a place to put all your add-on buttons without over-crowding the navigation bar.
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.
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.
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.
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!
Tamper Data Requires Restart Featured
Use tamperdata to view and modify HTTP/HTTPS headers and post parameters...
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.
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.
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.
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.
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.