Developer Tools

by Zulkarnain K.

50 Add-ons in this Collection

Firebug by Joe Hewitt, Jan Odvarko, others

Rated 4 out of 5 stars 2,101 reviews

1,340,121 users

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...

Stylish by userstyles.org

Rated 4 out of 5 stars 877 reviews

321,651 users

Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Tumblr, and many, many other sites. You can even customize Firefox and other programs themselves.

Web Developer by chrispederick

Rated 5 out of 5 stars 271 reviews

287,455 users

The Web Developer extension adds various web developer tools to the browser.

SQLite Manager by lazierthanthou

Rated 4 out of 5 stars 80 reviews

137,485 users

Manage any SQLite database on your computer.

Tamper Data by Adam Judson

Rated 4 out of 5 stars 162 reviews

68,785 users

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

ColorZilla by Alex Sirota

Rated 4 out of 5 stars 384 reviews

164,946 users

Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...

Lightbeam for Firefox by Mozilla

Rated 4 out of 5 stars 439 reviews

238,945 users

Lightbeam is a Firefox add-on that enables you to see the first and third party sites you interact with on the Web. Using interactive visualizations, Lightbeam shows you the relationships between these third parties and the sites you visit.

JSONView by Ben Hollis

Rated 5 out of 5 stars 177 reviews

85,036 users

View JSON documents in the browser.

JavaScript Deobfuscator by Wladimir Palant

Rated 4 out of 5 stars 25 reviews

32,347 users

This add-on shows you what JavaScript code runs on a web page, even if it is obfuscated and generated on the fly. Simply open JavaScript Deobfuscator from the Web Developer menu and watch the scripts being compiled/executed.

RESTClient, a debugger for RESTful web services. by Chao ZHOU

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.

Remote XUL Manager by Jorge Villalobos

Rated 5 out of 5 stars 37 reviews

73,041 users

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.

HttpFox by Martin Theimer

Rated 4 out of 5 stars 172 reviews

55,196 users

An HTTP analyzer addon for Firefox

Live HTTP Headers by Daniel Savard, Nikolas Co

Rated 4 out of 5 stars 174 reviews

87,224 users

View HTTP headers of a page and while browsing.

about:addons-memory by Nils Maier

Download Now

Experimental

Rated 4 out of 5 stars 134 reviews

18,241 users

Adds an about:addons-memory page that details add-on memory usage

DOM Inspector by SeaMonkey Council

Rated 5 out of 5 stars 73 reviews

71,915 users

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.
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