The top 25 most used Firefox add-on in Web Development category

Dark mode for every website. Take care of your eyes, use dark theme for night and daily browsing.

The best privacy tool and ad blocker extension for Firefox. Stop trackers, speed up websites and block ads everywhere including YouTube and Facebook.

FoxyProxy is an open-source, advanced proxy management tool that completely replaces Firefox's limited proxying capabilities. No paid accounts are necessary; bring your own proxies or buy from any vendor. The original proxy tool, since 2006.

Displays a country flag depicting the location of the current website's server and provides a multitude of tools such as site safety checks, whois, translation, similar sites, validation, URL shortening, and more...

Redesign your favorite websites with Stylus, an actively developed and community driven userstyles manager. Easily install custom themes from popular online repositories, or create, edit, and manage your own personalized CSS stylesheets.

Spoof websites trying to gather information about your web navigation—like your browser type and operating system—to deliver distinct content you may not want.

Easily save images with a wide range of customization features, such as file size, dimensions, and image type.

Make the web faster, more private, and more secure.

An easy-to-use tab reloader with custom reloading time settings for individual tabs

Clear browser cache with a single click or via the F9 key. F9 Fever! ;)

Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.

Delete browsing data directly from the browser toolbar. Clear cookies, history and cache with a single click.

Change the appearance of the web instantly

Tampermonkey is the world's most popular userscript manager.

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.

FireShot makes full page screen captures - http://bit.ly/RlBQMV Screenshots are quickly captured and: ― Saved as Image / PDF with links and text ― Sent to clipboard ― Printed Capture all open tabs or provide a list of the URLs for grabbing

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

Identify technologies on websites

Userscript support for browsers, open source.

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

Windscribe helps you circumvent censorship, block ads, beacons and trackers on websites you use every day.

DevTools extension for debugging Vue.js applications.

Cookie-Editor lets you efficiently create, edit and delete a cookie for the current tab. Perfect for developing, quickly testing or even manually managing your cookies for your privacy.

Easily override the browser's User-Agent string

Putting Flash back on the web. Designed to be easy to use, this extension will seamlessly enable you to play flash content, with no extra configuration required!