Fire Vox is a free and open source extension for the Mozilla Firefox web browser that transforms it into a self-voicing application. Easy to install and operate, it works on Windows, Mac, and Linux. It can work independently, or together with screen readers such as Orca. Since its debut in 2005, Fire Vox has garnered an increasing amount of interest in the accessibility community. It has several features not found in commercial screen readers, such as the ability to handle CSS 3 Speech Properties (resulting in it being cited as "the only implementation of aural style sheets"). It has also received mentions in several articles related to Firefox and/or web accessibility and even a mention in a techniques document from the W3C. As of February 2007, Fire Vox supports WAI-ARIA markup for AJAX live regions.
In November 2007, a new version of Fire Vox was released with built-in support for AxsJAX scripts. AxsJAX is a JavaScript framework that injects WAI-ARIA based accessibility into AJAX applications, and these scripts can be used without needing to be added to the web sites directly. These scripts are essentially Greasemonkey scripts for accessibility.
Fire Vox was last updated August 6, 2008. The version released by Chen is not currently compatible with Firefox 3.6 and higher. For this reason, Filippo Battaglia at Visilab Research Center of the University of Messina has released ML-FireVox that is compatible with any version of the browser and that supports both English and Italian voice.