A system and method for providing a user interface system to develop an application having a first component with descriptors expressed in a structured definition language and a second component expressed as a series of instructions. The individual components interact for processing messages on a runtime environment of a device that are received from a data source over a network. The component applications comprise data components, presentation components, and message components, which are written in XML code. The component applications further comprise workflow components which are written in a subset of ECMAScript, and are augmented with the XML code. The user interface system comprises a first module, such as a viewer or and editor, for developing the definitions of the first component through interaction with a data model that provides a persistent state of the application. The user interface system comprises a second module for developing the instructions of the second component through interaction with the data model. and a backend connector for providing the message mapping information of the data source to the first module. The first module generates the definitions based on the mapping information. The first and second components developed by respective the first and second modules are included in the application with other components where applicable.