Firefox Developer Tools is a set of web development tools built into the Firefox browser. It allows web developers and designers to quickly and easily inspect and debug their websites, web apps and HTML, CSS and JavaScript code. With Firefox Developer Tools, it is easy to identify and fix issues, as well as optimize the performance of websites and web apps. The tools also allow for development on multiple platforms including desktop and mobile. Features include: code editing, debugging, inspection of HTML, CSS, JavaScript and more. Additionally, the tools provide debugging across multiple platforms including Firefox OS, Android, Windows, and Mac OS X.
Discontinued The project is no longer being developed. The latest version, 0.8.14.1, released in May 2014, is not compatible with Firefox, but the extension still works in XUL-based Firefox forks such as https://alternativeapp.info/software/waterfox/ and https://alternativeapp.info / software / palemoon /