Mozilla Foundation (Freeware)

XULRunner is a runtime system for applications using XUL (XML User Interface Language). It is a major component of Mozilla’s codebase created to make development and deployment of Internet software easier. XUL, which users also refer to as the Mozilla platform, is the script utilized for building user interfaces of programs like Firefox. XML (Extensible Mark-up Language) is a standard all-purpose mark-up language that facilitates data exchange across various systems connected via the Web. Additionally, the runtime environment makes it possible to access functionalities of ActiveX Control. Programs using such application programming interface are able to function with the said system.  

XUL-based applications such as Mozilla Thunderbird, Mozilla Firefox, Songbird, Nightingale, Flickr Uploadr, Sunbird, SeaMonkey, TomTom Home 2.0, Conkeror, Miro, and Joost run on XULRunner. Video game series like the fourth instalment of Simon the Sorcerer, Simon Sorcerer 4: Chaos Happens, uses the program as well. Other applications that operate on the software include Lotus Notes, eMusic Remote, Google Adwords, Google Chrome, and Evergreen ILS.

Users can utilize the runtime environment to make development tools such as the AJAX Toolkit Framework. XULRunner’s developers aim to produce a Development Kit containing tools that build XUL extensions and applications. The tools will act as a developing environment that does away with the complex requirements of the Mozilla system for programs that are consists in XUL.