Internet content is increasingly accessible trough mobile devices. Part of this content is geodata in the form of maps that pose a technical challenge with regard to display size, data volume amongst others. One of the most popular map viewers is OpenLayers, whose mobile device capabilities will be worked on during the 5 day codesprint in Lausanne. The codesprint is being organised by swisstopo and camptocamp and terrestris is helping by sending its senior developer Marc Jansen, who co-wrote the book “OpenLayers – Webentwicklung mit dynamischen Karten und Geodaten” (only available in german).