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
1,783 users

webhint
Check for best practices and common errors with your site's accessibility, speed, security and more.
Rated 4.6 out of 5webhint
2,197 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
31,247 users

Augury
Extends the Developer Tools, adding tools for debugging and profiling Angular applications.
Rated 3.7 out of 5Rangle.io
1,113 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
3,010 users

Compat Report
Shows a report of browser compatibility issues using data from MDN
Rated 4.6 out of 5Eduardo Bouças
375 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
533 users

Web Developer
The Web Developer extension adds various web developer tools to the browser.
Rated 4.3 out of 5chrispederick
67,436 users

axe DevTools® - Web Accessibility Testing
Add accessibility auditing to the Firefox Developer Tools
Rated 4.2 out of 5Deque Systems Inc.
10,382 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
1,701 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
1,561 users

41,199 users

57,596 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
168,599 users