Firebug was a FireFox extension (lite version released for Chrome) that made live debugging of website code possible. Firebug saw several versions released over the years before it was discontinued in favor of FireFox Development Tools, which is new default debugging tool included in the latest FireFox build.
- Fully open source
- Syntax highlighting for easy editing
- DOM Event Inspector to handle events
- Fully open source
- Available for FireFox and Chrome
- Allows live debugging of website code
- Flash and Flex development required paid add-on
Firebug is the foundation that the current Firefox Development Tool is built upon for debugging code in Firefox. It was first conceived in 2006 by Joe Hewitt and quickly became the best way to monitor AJAX code in any modern browser. With the popularity of the extension, it was soon open sourced and developed into a more robust debugging tool that could handle language syntax and more types of code monitoring. Around 2010, the app debuted for Google Chrome as Firebug Lite, though the Chrome extension was never given much focus beyond its initial release. In fact, it hasn't been updated since 2011, which was only a year after it debuted on the Chrome Web Store. The Firebug devs announced the retirement of Firebug in 2017, after the most recent Firefox Quantum update. The new Firefox Development Tools that released with that browser is based on Firebug and therefore made the extension redundant. You can still download it for older versions of Firefox, but it is no longer being maintained or developed in favor of Firefox's built-in debugging tool. Firebug is an excellent example of how community-led extension development can work to improve a product overall. Every single feature that was available in Firebug is now available in Firefox Development Tools, with more being added as the service evolves. If you're still using an older version of Firefox that is still compatible with Firebug, you can download the extension from the main website. The extension source code and other files are available too if you'd like to examine the source to determine how the extension works.