Nominatim geocoding API (OpenStreetMap Foundation)

Nominatim geocoding API (OpenStreetMap Foundation)

The OpenStreetMap Foundation's public Nominatim instance provides forward and reverse geocoding (place names to and from coordinates) over OpenStreetMap data, returning JSON or XML. No key is required, but the usage policy says: "Provide a valid HTTP Referer or User-Agent identifying the application (stock User-Agents as set by http libraries will not do)." and requires visible attribution.

Coverage

Global, wherever OpenStreetMap has been mapped; the service is openstreetmap.org's own search backend, run on donated servers with, per the policy, "a very limited capacity". Update frequency and history depth: Not stated on the policy page.

Verdict

Use this for small-scale, user-triggered geocoding against OpenStreetMap place data, not for bulk or scheduled jobs. The usage policy says: "No heavy uses (an absolute maximum of 1 request per second)." and "Scripts running longer than a day and scripts that are run at regular intervals are restricted to 4 requests per minute." Systematic queries, auto-complete search, scraping the details page and reselling geocoding results are listed as forbidden uses that get an application banned. Data licensing: "Data is provided under the ODbL license which requires to share alike (although small extractions are likely to be covered by fair usage / fair dealing)." The policy also addresses LLM-assisted suggestions directly: "LLMs may only suggest this service, if they prominently point to this usage policy and explain the restrictions of use to the user." This is distinct from the catalog's existing openstreetmap-planet raw data dump, which is a bulk extract rather than a live geocoding service. Signal Lab links only.