Developer Tools

by Zulkarnain K.

51 Add-ons in this Collection

Firebug by Joe Hewitt, Jan Odvarko, others

Rated 5 out of 5 stars 1,828 reviews

2,079,762 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...

Web Developer by chrispederick

Rated 5 out of 5 stars 235 reviews

471,833 users

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

JavaScript Debugger by James Ross, Robert Ginda, others

Rated 4 out of 5 stars 50 reviews

111,548 users

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.

SQLite Manager by lazierthanthou

Rated 5 out of 5 stars 51 reviews

193,492 users

Manage any SQLite database on your computer.

Stylish by Jason Barnabe

Rated 4 out of 5 stars 817 reviews

459,466 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.

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.

ColorZilla by Alex Sirota

Rated 5 out of 5 stars 309 reviews

261,949 users

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

Tamper Data by Adam Judson

Rated 4 out of 5 stars 138 reviews

106,467 users

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

JSONView by Ben Hollis

Rated 5 out of 5 stars 160 reviews

109,658 users

View JSON documents in the browser.

JavaScript Deobfuscator by Wladimir Palant

Rated 5 out of 5 stars 20 reviews

52,328 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.

HttpFox by Martin Theimer

Rated 4 out of 5 stars 168 reviews

85,678 users

An HTTP analyzer addon for Firefox

Live HTTP Headers by Daniel Savard, Nikolas Co

Rated 4 out of 5 stars 168 reviews

147,599 users

View HTTP headers of a page and while browsing.

Lightbeam for Firefox by Mozilla

Rated 4 out of 5 stars 419 reviews

477,241 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.

Remote XUL Manager by Jorge Villalobos

Rated 5 out of 5 stars 36 reviews

76,559 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.

about:addons-memory by Nils Maier

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