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
2,209 users

webhint
Check for best practices and common errors with your site's accessibility, speed, security and more.
Rated 4.6 out of 5webhint
2,667 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
38,627 users

Augury
Extends the Developer Tools, adding tools for debugging and profiling Angular applications.
Rated 3.7 out of 5Rangle.io
1,433 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
3,381 users

Compat Report
Shows a report of browser compatibility issues using data from MDN
Rated 4.6 out of 5Eduardo Bouças
478 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
620 users

Web Developer
The Web Developer extension adds various web developer tools to the browser.
Rated 4.3 out of 5chrispederick
77,013 users

axe DevTools® - Web Accessibility Testing
Add accessibility auditing to the Firefox Developer Tools
Rated 4.5 out of 5Deque Systems Inc.
10,231 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
2,108 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
1,879 users

48,772 users

68,506 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
185,195 users