A system for developing an application program having functionality that corresponds to a finite state machine (FSM) model includes a visual interface that generates a graphical environment on a display for displaying an FSM model representing functionality of the program, a dynamic state machine processor that uses XML descriptions associated with the FSM model to generate the program executed at run-time, and an extensible graphic user interface that provides the end-user interface features to the end-user as generated during run-time by the processor based on the FSM model.