A widget engine renders widgets using operating system platform-specific attributes. A widget application written at least partly in platform non-specific code is rendered by the widget engine through a series of system calls and callbacks. Upon interpreting particular code, the widget engine issues a system call to a module for performing a particular type of action. The module, based on the operating system platform, calls a platform-specific library that specifies how to carry out the action according to the operating system platform. Thereafter, using the returned platform-specific data, the widget engine renders the widget.