Build, test, scale and more with the only browser built just for developers. Welcome to your new favorite browser. Get the latest features, fast performance, and the development tools you need to build for the open web.

All the latest developer tools in beta, plus experimental features like the Multi-line Console Editor and WebSocket Inspector. A separate profile and path so you can easily run it alongside Release or Beta Firefox. Preferences tailored for web developers: Browser and remote debugging are enabled by default, as are the dark theme and developer toolbar button

Features:

Inactive CSS:
Firefox DevTools now grays out CSS declarations that don’t have an effect on the page. When you hover over the info icon, you’ll see a useful message about why the CSS is not being applied, including a hint about how to fix the problem.

Firefox DevTools:
The new Firefox DevTools are powerful, flexible, and best of all, hackable. This includes a best-in-class JavaScript debugger, which can target multiple browsers and is built in React and Redux.

Master CSS Grid:
Firefox is the only browser with tools built specifically for building and designing with CSS Grid. These tools allow you to visualize the grid, display associated area names, preview transformations on the grid and much more.

Fonts Panel:
The new fonts panel in Firefox DevTools gives developers quick access to all of the information they need about the fonts being used in an element. It also includes valuable information such as the font source, weight, style and more.

Build and Perfect your sites with Firefox DevTools
• Inspector: Inspect and refine code to build pixel-perfect layouts.
• Console: Track CSS, JavaScript, security and network issues.
• Debugger: Powerful JavaScript debugger with support for your framework.
• Network: Monitor network requests that can slow or block your site.
• Storage panel: Add, modify and remove cache, cookies, databases and session data.
• Responsive Design Mode: Test sites on emulated devices in your browser.
• Visual Editing: Fine-tune animations, alignment and padding.
• Performance: Unblock bottlenecks, streamline processes, optimize assets.
• Memory: Find memory leaks and make your application zippy.
• Style Editor: Edit and manage all your CSS stylesheets in your browser.

Requirements:
macOS 10.12+
Universal Binary