The SEFAGI project takes place in domains where many different user interfaces are needed in the same application. Instead of manually developing all the required windows, we propose a platform that automatically generates the needed code from high level descriptions of these windows. Code generation is done for standard screens and for small screens on mobile terminals. New windows are automatically taken in charge by an execution layer on the terminal. Data adaptation to the different terminals is also provided. A platform-independent window description language has been defined