This disclosure relates to cross-platform applications that include native and non-native components on mobile devices. An exemplary method generally includes receiving a first workflow step definition including a first set of widgets to be loaded into an application shell. A mobile shell identifies a type of each widget in the first set of widgets (e.g., native or platform-agnostic) and loads each widget into the mobile shell based on the widget type. For a platform-agnostic widget, the mobile shell creates a platform-agnostic widget proxy service, which provides a runtime environment. The platform-agnostic widget may be loaded into the platform-agnostic widget proxy service and executes in the runtime provided thereby.