: The need for support of multi-user interaction is growing in several application domains, including the Web. However, there is a lack of tools able to support designers and developers of multi-user, multi-device interactive applications. In this paper we present a proposal for this purpose describing how it can provide support at both design and run-time. The design and development process can start with task model descriptions and such logical information is used to generate interfaces adapted to the target platforms and mechanisms for their coordination at run-time. Key words: Multi-User, Multi-Device User Interfaces, Authoring environments, Modelbased design, Software architectures.