The Canton of Geneva’s geoportal (www.sitg.ch) is one of the most visited geoportals in Switzerland. In order to increase its visibility even more and to satisfy the needs of its mobile users, the State of Geneva chose arx iT to develop a mobile version for tablets and smartphones (Android and iOS). The biggest challenge consisted in creating a single application that could fill the needs of both a citizen that doesn’t know GIS and an expert (research firm, architect, etc.) with important expectations for GIS functionalities, such as geographical data edition. In addition to that, we paid a special attention to the graphical design and the ergonomics of the application to ensure that it is easy and intuitive to use.