Web Development



Control what gets sent as the HTTP Referer on a per-site basis.

Rated 4 out of 5 stars (180)
845 weekly downloads

Auto Refresh

Auto Refresh will refresh or hard refresh any tab or group of tabs at individual or group intervals.

You can also customize your presets and save the ones you most use.


Rated 3 out of 5 stars (38)
800 weekly downloads


This extenion is GUI Front-end of "about:cache"...

Rated 4 out of 5 stars (220)
760 weekly downloads

Clear Console Featured

One click to clear your cache, cookies, history, html5/local storage, http logins, all of them or restart your browser with/without notifications.

Rated 4 out of 5 stars (60)
710 weekly downloads

SEO Toolbar by Moz

Get SEO metrics while you surf! For each page you visit, see metrics like Domain and Page Authority, analyze links, expose page elements, and access other SEO tools. Next version will be for both Firefox and Chrome. Stay tuned!(This is version 2.6.5)

Rated 4 out of 5 stars (39)
692 weekly downloads

Favorites (Selenium IDE)

A plugin for Selenium-IDE to have favorite test suites and open and execute the test suites with a single click

Rated 4 out of 5 stars (3)
685 weekly downloads


A developer tool for interacting with web services and other web resources that lets you make HTTP requests, set the entity body, and content type. This allows you to interact with web services and inspect the results...

Rated 4 out of 5 stars (61)
679 weekly downloads

Classic Toolbar Buttons No Restart Featured

'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7s small view, Fx 4-12s large view & Tb 5-14) for current Firefox, Thunderbird and Seamonkey versions on Windows.

Beta builds on versions page!

Rated 5 out of 5 stars (144)
677 weekly downloads

Cookie Importer

Imports cookies from a textfile.
Reads Netscape standard cookies.txt files as exported by IE and others.
Very useful in combination with the Cookie Exporter add-on.

Rated 5 out of 5 stars (2)
674 weekly downloads

Font Finder Featured

FontFinder is created for designers, developers and typographers. It allows a user to analyze the font information of any element on a page, copy any piece(s) of that information to the clipboard, and perform inline replacements to test new layouts.

Rated 4 out of 5 stars (67)
657 weekly downloads

Quick Locale Switcher

Allows you to quickly switch to a different language (User Interface, Spell Checker Dictionary and Website content) in your Mozilla application.

Rated 3 out of 5 stars (85)
627 weekly downloads

Html Validator

HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon

For Online HTML 5 validation, you need 0.962

Rated 4 out of 5 stars (210)
616 weekly downloads


Debug Flash/SWF files on the web. Edit properties and inspect elements on the fly. View log output inside the extension. Run AS3 code against the active SWF. Access assets with the Explorer. View AMF calls and Shared Objects and much much more...

Rated 4 out of 5 stars (5)
607 weekly downloads

Pearl Crescent Page Saver screenshot tool

Save an image of a web page (including Flash content) to a file. Web page screenshots may be captured interactively or from the command line. Options allow you to control the output format (PNG or JPEG), image file name, scaling, and much more.

Rated 4 out of 5 stars (79)
593 weekly downloads

Remote XUL Manager No Restart

Manages the Remote XUL whitelist to allow websites and local files to load XUL content. For versions compatible with Firefox 41 and lower, see All Versions page below.

Rated 5 out of 5 stars (35)
582 weekly downloads

XPath Checker

An interactive editor for XPath expressions.

Rated 5 out of 5 stars (18)
579 weekly downloads


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 (227)
568 weekly downloads

Easy Copy Featured

Copy links to a page with one click, ready to paste anywhere else, eg. emails, blogs, forums and Twitter. Copy a single page, all open tabs or all links on a page.

Rated 5 out of 5 stars (29)
565 weekly downloads


A debug tool for Flash developers enabling switching between Flash player versions and basic debug log viewing.

Flash icon from PraX-08's Qure CS4 icon set.

Rated 5 out of 5 stars (11)
559 weekly downloads

Selenium IDE

Selenium IDE is an integrated development environment for Selenium tests. It is implemented as a Firefox extension, and allows you to record, edit, and debug tests.

Rated 5 out of 5 stars (1)
545 weekly downloads