Mozilla has released Firefox 3 beta 1, targeted for web developers and the testing community. Based on the Gecko 1.9 engine – which has been under development for 27 months, consisting of nearly two million lines of code – the beta is designed to showcase Firefox's increased performance, stability, and security, while maintaining an easy to use, customizable interface. Firefox 3 beta 1 brings malware and web page forgery protection, as well as a button that displays security information for the current site. The new version automatically checks plugin versions and can disable older, insecure versions, as well as preventing automatic plugin updates if the connection method is insecure. Antivirus integration will inform any active antiviral software when it is downloading a file, and the new SSL error pages provide clearer definitions and deal with problematic content in a stricter manner.

In addition to increased speed and reliability, Mozilla has made a number of refinements enhancing ease-of-use and personalization. A new download manager increases efficiency when looking for transferred files, and Firefox now supports resumable downloads. Web pages can be zoomed into, scaling the layout, text, and images for better visability. Plugins can now be enabled and disabled in the Add-on Manager, and web based protocols such as "mailto:" links will now coordinate with web sources, such as a webmail client. At its current stage, Firefox 3 beta 1 offers over 30 fixes and additions, and Mozilla says that more will be added and refined as the beta stage progresses.