Web Developer's Toolbox
Speed up the development process by using add-ons to troubleshoot, edit, and debug web projects without ever clicking away from Firefox.
- 15
- Add-ons
- Firefox
- Creator
- Feb 16, 2024
- Last updated

Feature Queries Manager
Manage and toggle CSS on a page behind a @supports Feature Query.
Rated 4.2 out of 5ireaderinokun
2,100 users

webhint
Check for best practices and common errors with your site's accessibility, speed, security and more.
Rated 4.6 out of 5webhint
2,454 users

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 4.3 out of 5Selenium
35,197 users

Augury
Extends the Developer Tools, adding tools for debugging and profiling Angular applications.
Rated 3.7 out of 5Rangle.io
1,340 users

Fontanello
A browser extension that lets you display the basic typographic styles of a text by right-clicking it.
Rated 4.7 out of 5Fred Bergman
3,091 users

Compat Report
Shows a report of browser compatibility issues using data from MDN
Rated 4.6 out of 5Eduardo Bouças
432 users

ChromeLogger
Parses and displays messages from X-ChromeLogger-Data and X-ChromePHP-Data headers in DevTools Web Console facilitating server-side debugging via the Chrome Logger protocol ( https://craig.is/writing/chrome-logger/ ).
Rated 4.6 out of 5BurningMoth
572 users

Web Developer
The Web Developer extension adds various web developer tools to the browser.
Rated 4.3 out of 5chrispederick
71,537 users

axe DevTools® - Web Accessibility Testing
Add accessibility auditing to the Firefox Developer Tools
Rated 4.5 out of 5Deque Systems Inc.
8,879 users

Laboratory (Content Security Policy / CSP Toolkit)
Because good website security shouldn't only be available to mad scientists! Laboratory is a WebExtension that helps you generate a Content Security Policy (CSP) header for your website.
Rated 4.6 out of 5April King
1,919 users

DevTools Media Panel
DevTools panel that displays technical details about media elements and webrtc on the current page; intended primarily for web developers to understand media playback issues on their sites, and for users to provide more informative bug reports.
Rated 4.3 out of 5Karolien Koorts
1,791 users

44,366 users

63,272 users

React Developer Tools
React Developer Tools is a tool that allows you to inspect a React tree, including the component hierarchy, props, state, and more. To get started, just open the Firefox devtools and switch to the "⚛️ Components" or "⚛️ Profiler" tab.
Rated 4.6 out of 5React
170,165 users