Firefox add-ons with "Programming" tag

Finally, an efficient wide-spectrum content blocker. Easy on CPU and memory.

Userscript support for browsers, open source.

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.

Customize the way a web page displays or behaves, by using small bits of JavaScript.

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.

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

DevTools extension for debugging Vue.js applications.

DevTools for Redux with actions history, undo and replay.

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.

Quickly translate Japanese by hovering over words. Formerly released as Rikaichamp.

A firefox addon allowing the user to enable CORS everywhere by altering http responses. Report issues to the repository, with enough information to reproduce the problem: https://github.com/spenibus/cors-everywhere-firefox-addon/issues

View JSON documents in the browser.

Zoom images/videos on all your favorite websites (Facebook, Amazon, etc). Simply hover your mouse over the image to enlarge it.

This extension is very useful for PHP developers that are using PHP tools with Xdebug support like PHPStorm, Eclipse with PDT, Netbeans and MacGDBp or any other Xdebug compatible profiling tool like KCacheGrind, WinCacheGrind or Webgrind.

Manage browser's requests, include modify the request headers and response headers, redirect requests, cancel requests

Add, modify or remove a header for any request.

Everything can be scripted, allowing your browser to do more!

Fast JSON viewer - highlights, shows items count/size, handles large files

Add, modify or remove a header for any request on desired domains.

A REST client for almost any web service.

Easily add (Access-Control-Allow-Origin: *) rule to the response header.

A mobile devtools for debugging web sites and applications with the console, DOM, network info, sources, and more.

Open-source browser automation, desktop automation and RPA for Firefox: record macros, scrape data, fill forms, and automate with OCR, image recognition and AI. Created macros run locally in your browser, not in the cloud.

Displays markdown documents beautified in your browser.

No more CORS error by appending 'Access-Control-Allow-Origin: *' header to local and remote web requests when enabled