Is there a reason there's no API token?

[drewg2009]

Curious if there's a reason why there's no API Authentication or token shown in the docs?

What happens of a user application or user sends a lot of requests, will the availability of the service be affected? Are there rate limits?

[otbutz]

AFAIK there's no DoS protection or the like built into Nominatim itself. The public instance is a bit different: https://operations.osmfoundation.org/policies/nominatim/

[lonvia]

If you are talking about https://nominatim.openstreetmap.org, then you should be aware that this is the instance for the OpenStreetMap community, which we just happen to keep open to the public to give people the possibility to experiment and explore. It is not meant for heavy use. There is rate limiting in place to restrict the most notorious abusers but in general we trust that users behave and respect that this is a shared resource that is provided for the benefit of everybody.

If you do need to worry about availability or expect high usage, then have a look at alternative commercial providers. Some are listed in the wiki . Alternatively, Nominatim is just a piece of software. You can easily install and run it on your own server.