GraphHopper is a road routing library written in Java and provides a web interface called GraphHopper Maps. As well as a routing API over HTTP. It runs on the server, desktop, Android, iOS or Raspberry Pi. By default OpenStreetMap data for the road network and elevation data from the Shuttle Radar Topography Mission is used.GraphHopper can be configured to use different algorithms such as Dijkstra, A* and its bidirectional versions.