Web Development

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Disconnect Featured

Make the web faster, more private, and more secure.

Rated 4 out of 5 stars (136)
264,075 users

ColorfulTabs Featured

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 (966)
263,461 users

Awesome Screenshot Plus - Capture, Annotate & More No Restart

Capture the whole page or any portion, annotate it with rectangles, circles, arrows, lines and text, blur sensitive info, one-click upload to share. And more!

Rated 4 out of 5 stars (1,036)
226,370 users

SQLite Manager

Manage any SQLite database on your computer.

Rated 5 out of 5 stars (30)
220,810 users

Text Link

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

Rated 4 out of 5 stars (266)
208,149 users

Live HTTP Headers

View HTTP headers of a page and while browsing.

Rated 4 out of 5 stars (153)
203,769 users

Image Zoom

Adds zoom and rotation functionality for images...

Rated 4 out of 5 stars (327)
195,005 users

JavaScript Debugger

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 (48)
178,391 users

MeasureIt

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

Rated 4 out of 5 stars (327)
176,563 users

IE Tab + (FF 8+, 7, 6, 5, 4, 3.6, 3.5, SeaMonkey)

IE Tab + is an enhanced version of IE Tab. It supports FF 3.5 or greater, integrates IE Tab with Adblock Plus in the IE Tab engine, and synchronizes cookies between IE and Firefox. You can easily import settings from the original IE Tab into IE Tab +

Rated 3 out of 5 stars (82)
168,825 users

Clear Cache Button

Adds a clear cache toolbar button. After installing the extension, find the clear cache button in the toolbar customization...

Rated 4 out of 5 stars (128)
165,843 users

Screengrab (fix version) Featured

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

Rated 5 out of 5 stars (238)
159,949 users

DOM Inspector

DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.

Rated 5 out of 5 stars (59)
155,063 users

Modify Headers

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 (70)
154,327 users

RESTClient, a debugger for RESTful web services.

Notice: some important features (XML indentation and load old saved requests) are missing in version 2.0.0, please update to version 2.0.1.

Please follow the link ("View other versions") below To install version 2.0.1.

Rated 4 out of 5 stars (75)
147,533 users

The Addon Bar (Restored) No Restart Featured

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

Rated 5 out of 5 stars (252)
145,621 users

YSlow

YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance web pages.
http://yslow.org is the official open source website.

Rated 3 out of 5 stars (180)
134,239 users

RequestPolicy

Be in control of which cross-site requests are allowed. Improve the privacy of your browsing by not letting other sites know your browsing habits. Secure yourself from Cross-Site Request Forgery (CSRF) and other attacks.

Rated 4 out of 5 stars (209)
128,809 users

Cookies Manager+

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 4 out of 5 stars (69)
116,093 users

HttpFox

An HTTP analyzer addon for Firefox

Rated 4 out of 5 stars (159)
115,018 users