Manage and toggle CSS on a page behind a @supports Feature Query.
Debug and test tag management (Google Tag Manager, Adobe Launch / DTM, Tealium) and analytics (Google Analytics, Adobe Analytics) implementations from within Developer Tools.
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.
A powerful optical character recognition (OCR) extension to capture and convert images to text
A beautiful feature-rich GraphQL Client for all platforms.
Emulate WebXR devices on your browser
Kill your css layout bugs!
Pesticide is an open source CSS tool created by Adam Morse and available for download, forking on Github at http://pesticide.io/
Measure page elements size in pixel with an easy-to-use ruler.
Adds a simple button to inject a Xdebug cookie. Compatible with Firefox 57+ (Quantum).
It is a port of "The easiest Xdebug" Addon by Nikita Nikitin, which is not compatible with WebExtensions.
Open your Microsoft Visio files for free
Provides better experience for using the Hoppscotch web app.
Haven't used Hoppscotch ? It's an amazing quick API Request Builder.
Try it at https://hoppscotch.io/ !!!
Automatically highlight and count all occurrences of a word by selecting it.
Custom mode option provides multiple highlighting feature with customizable colors and can also display search markers beside the scrollbar.
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.
Browser devtools extension for debugging Svelte applications.
CSS Reloader is an extension that allows you to reload all the CSS of any site without you have to reload the page itself.
Download and optimize icons, logos, and vector SVGs from websites. SVG Gobbler hunts down the SVG content in your current tab, highlights unique attributes about it and gives you the option to download or copy to clipboard.
SmartProxy is a smart automatic proxy switcher that will automatically enable/disable proxy for the sites you visit, based on customizable rules.
A Handy Console / Client to Communicate with WebSocket Servers
An extension to help you gain full control of any website by redirecting traffic, replacing, editing, or inserting new content.
Adds MetaMask's legacy window.web3 API to your browser
when activated, interrupts the built-in download manager to direct links to FlashGet
A find-in-page extension with support for regular expressions.
Ever wish that Firefox didn't use color management when viewing images or video? Turn it off easily with this add-on.
Outlines nofollow links, detect nofollow and noindex meta tags on webpages. Features website filtering and custom CSS outline styles
This is an extension that allows you to easily check SEO-related meta information and copy it with one click.
Copy content from web powerful than ever before.
HackBar Quantum is a sidebar that assists you with web application security testing, it's aim is to help make those tedious tasks a little bit easier. This add-on is a predecessor to the original HackBar that is not compatible with Firefox Quantum.
Display info for the current image in a new window, new tab, or overlaid on the image. Convert WEBP images to PNG or JPEG. Send an image URL to TinEye for reverse image search. "View image..." in same tab? Check the screenshots for all the options.
Save any images in page directly from context menu, this includes svg elements, css background images and direct child images.
Create rulers and grids overlays to help develop your web applications