Creating Multi-Platform User Interfaces with RenderXML Francisco M. Trindade 1 , Marcelo S. Pimenta 1 1 Federal University of Rio Grande do Sul - Institute of Informatics Av. Bento Gonçalves, 9500 - Bloco IV Porto Alegre, RS – Brazil {fmtrindade, mpimenta}@inf.ufrgs.br ABSTRACT As the technology evolves, the existence of different computational devices has made ad- hoc software development no longer acceptable in the development of multi-platform software applications. This article describes RenderXML, a software tool developed to facilitate the creation of multi-platform applications. RenderXML acts as a renderer, mapping concrete user interfaces (UI) described in UsiXML to multiple platforms, and also as a connector, linking the rendered UI developed in one language to functional core code developed possibly in a different programming language. Categories and Subject Descriptors H.5.2 [Information Interfaces and Presentation]: User Interfaces - Graphical user interfaces (GUI), Evaluation/methodology, Prototyping. General Terms Design, Experimentation, Human Factors, Languages. Keywords Multi-platform, UsiXML, Rendering, User Interface. INTRODUCTION Computer software development has nowadays as an important requirement the possibility of execution in more than one platform, either through desktop computer, handhelds or mobile phones. To address this demand, ad-hoc software development is no longer acceptable in terms of the cost and time required for software construction and maintenance. In this way, many research projects are being developed in order to allow the creation of software applications that can be executed in multiple use contexts, with minimal alteration of its algorithm. One of the proposed solutions is the development user interfaces (UI) with plasticity, capable of adapting themselves to different use contexts. In order to obtain plasticity, High-level UI Descriptions (HLUID) are commonly used,