osrmrouted

osrmrouted, commonly referred to as osrm-routed in deployments, is the routing daemon at the heart of the Open Source Routing Machine (OSRM) project. It serves the OSRM HTTP API to compute routes and related queries, such as distance matrices and route matching. The daemon operates as a server process that accepts requests over HTTP and returns routing results in JSON format.

The core function of osrmrouted is to load a preprocessed routing graph from a dataset on startup. This dataset is produced by the OSRM preprocessing workflow for a chosen profile (for example, car, bike, or foot) and stored in a directory containing the .osrm files and associated metadata. The graph is kept in memory to enable fast query responses. Preprocessing typically involves generating routing indices and shortcuts using algorithms such as Contraction Hierarchies (CH) or Multilevel Dijkstra (MLD), depending on the chosen configuration and data.

During operation, osrmrouted listens on a configurable port and uses a multi-threaded design to handle multiple requests concurrently. Command-line options let operators select the routing algorithm, define the number of worker threads, specify the network port, and adjust other runtime parameters. The API endpoints supported by osrmrouted include route for path calculations, nearest for locating the closest network node, table for distance or time matrices, and match for map matching of GPS traces, among others. Responses typically include distance, duration, and, when requested, route geometry.

osrmrouted is designed for server deployments and is suitable for runs in traditional servers, containerized environments, or embedded setups. It is typically used behind a reverse proxy or load balancer and forms a core component of applications that require fast, scalable routing capabilities.