The new Firefox Beta 1 is 9 MB in size, but will occupy 52 MB on PC. It comes with a new Add-ons manager as well as JetPack SDK support, which enables users to install plug-ins without restarting the browser. Firefox 4 is a major upgrade from its predecessors, features enhanced HTML5 support, hardware-accelerated HD video and WebSockets.

In the Firefox Beta 1, security improvements have also been added to better hide browsing history that in some circumstances could be retrieved using previous browsers. Firefox 4 also introduces support for out-of-process plugins (OOPP) on OS X for the first time. Mozilla has chosen to support HTML 5 video playback by implementing Google's WebM video codec.

Firefox 4 beta now has the browser tabs pointing upwards by default instead of hanging down from the top of the window. In the new launched web browser of Mozilla, crash protection is there, that prevents bad plugins from blowing up the whole browser. There are others lot of features available on the Firefox 4 Beta 1.