Diverse operating systems and developed platforms of mobile devices are implemented by vendors exist. The software has to be developed by respective environment in designing the user interface of software. For the solution of the inconvenience, this paper proposes an integrated platform 4A DUOS for developing user interface independently. The proposed platform can use web language not dependent on various operating systems, and offer online access to API and component templates to provide the convenience of the user interface design. Also, the server with on board designed user interface implements the service to the user. Therefore, the users can design the independent user interface on various mobile devices by using only one source.