A system and method for developing an application for execution on a target device is described. The system comprises: a processor and a memory for storing instructions and data to configure the processor to provide: a development platform interface for developing a presentation component for output by the target device to a user interface in accordance with a target device appearance definition; a plurality of development platform appearance definitions for configuring the appearance of output of the development platform interface; and a mapping mechanism for mapping between the target device appearance definition and a corresponding development platform appearance definition to simulate on the system the output of the presentation component by the target device.