Nominatim review 2026: how this open-source OpenStreetMap geocoding tool works, usage policy, self-hosting, and the best geocoding API alternatives.
Nominatim is the open-source geocoding engine that powers the search box on the official OpenStreetMap website. It converts place names and addresses into geographic coordinates (geocoding) and coordinates back into human-readable addresses (reverse geocoding), using OpenStreetMap data as its sole data source.
It was created by Brian Quinion and is maintained as a community project under the OpenStreetMap Foundation, with development happening in the open on GitHub under the osm-search organization.
Nominatim is built on osm2pgsql's gazetteer output mode and a PostgreSQL/PostGIS backend, with search and indexing logic written in C, PL/pgSQL, and Python. The public instance handles an extremely high volume of daily queries for the main OSM website.
Because it is fully open source, it can be self-hosted by importing OpenStreetMap data extracts (regional or full-planet) into a local PostgreSQL/PostGIS database, giving organizations full control over rate limits, uptime, and data freshness without depending on the shared public API.
Nominatim itself is completely free and open source with no licensing cost. The public API at nominatim.openstreetmap.org is free to use but governed by a strict usage policy limiting request rates and prohibiting heavy automated/bulk use to protect shared infrastructure.
Organizations needing higher volume or guaranteed uptime typically either self-host Nominatim (free software, but requiring their own server and data-import costs) or pay a third-party provider such as Geoapify, LocationIQ, or MapTiler for managed, rate-limit-free Nominatim-based geocoding APIs.
Yes, Nominatim is completely free and open source software, and its public API is free to use within the OpenStreetMap Foundation's usage policy rate limits.
Nominatim was originally created by Brian Quinion and is now maintained by open-source volunteer contributors under the OpenStreetMap Foundation.
Yes, Nominatim can be self-hosted by importing OpenStreetMap data into a PostgreSQL/PostGIS database, giving unlimited private query volume without relying on the shared public API.
Nominatim uses exclusively OpenStreetMap data, the free, community-maintained global map dataset.
Yes, the public instance at nominatim.openstreetmap.org enforces strict rate limits and prohibits heavy automated or bulk querying to protect shared infrastructure.
Common alternatives include Google Maps Geocoding API, Mapbox Geocoding, HERE Geocoding, and other open-source projects such as Photon and Pelias.
Yes, third-party providers such as Geoapify, LocationIQ, and MapTiler offer managed, rate-limit-free Nominatim-based geocoding APIs as a paid service.