About this Collection
Add-ons for web development and extension development.
50 Add-ons in this Collection
Firebug by Joe Hewitt, Jan Odvarko, others
Stylish lets you customize any website with custom user styles (themes for websites). Choose from the largest userstyles library to change the color scheme, background, and skin for Google, Facebook, YouTube and many, many more sites.
The Web Developer extension adds various web developer tools to the browser.
RESTClient has been completely rewritten for compatible with Firefox 57. Some functions are still missing (OAuth & OAuth 2.0 authentication).
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
Use tamperdata to view and modify HTTP/HTTPS headers and post parameters...
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.
View HTTP headers of a page and while browsing.
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.
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
Feature rich XPath generator, editor, inspector and simple extraction tool...