Adapting a graphical user interface (GUI) to a variety of resources with different capabilities is one of the most interesting questions of today’s mobile computation. The GUI constructed for one application should be usable on different interactive devices, e.g. WebTV terminals, WAP phones or Java-enabled devices. In this paper, we discuss existing solutions and present a solution based on mobile agents. Mobile agents construct their GUI using third-party eXtensible User interface Language (XUL), jXUL middleware and XSL transformations. Mobile agents move to host computers and then build their GUI, or act as a proxy to devices without sufficient processing capabilities (e.g., WAP devices). The result is an adaptable GUI platform that can be run on multiple devices without modifications, supporting different resources and architectures. We show the application of this approach by implementing a mobile currency converter and survey.