In spite of the apparent facility of building Web pages using current visual environments, the development on the Web application remains a complex task. As for other complex software one possible and promising way of dealing with this complexity is model-based approach. In this paper we present SWCEditor, a model-based tool (exploiting the StateWebCharts notation) aiming at supporting designers to build navigation models of Web applications. The StateWebCharts (SWC) notation is a formalism that provides abstract mechanisms to build navigation models of Web applications. This paper presents the SWCEditor, a tool supporting the creation, edition, visualisation and simulation of SWC models.