How to hit the Nominatim (OpenStreetMap) API

Nominatim at https://nominatim.openstreetmap.org turns addresses and place names into coordinates, and coordinates back into addresses, using OpenStreetMap data.

Authentication

None, but the public server's usage policy allows at most one request a second, requires an identifying User-Agent, and forbids heavy use — run your own instance for bulk geocoding.

Full reference: https://nominatim.org/release-docs/latest/api/Overview/

Reverse geocode

Coordinates to an address.

curl "https://nominatim.openstreetmap.org/reverse?lat=40.7484&lon=-73.9857&format=json"
Run in PostTaco
Example response (trimmed)
{
  "place_id": 358431881,
  "licence": "Data © OpenStreetMap contributors, ODbL 1.0. http://osm.org/copyright",
  "osm_type": "node",
  "osm_id": 13306330095,
  "lat": "40.7484257",
  "lon": "-73.9856700",
  "class": "tourism",
  "type": "viewpoint",
  "place_rank": 30,
  "importance": 0.00009175936522464359,
  "addresstype": "tourism",
  "name": "",
  "display_name": "350, 5th Avenue, Koreatown, Manhattan Community Board 5, Manhattan, New York County, New York, 10118, United States",
  "address": {
    "house_number": "350",
    "road": "5th Avenue",
    "neighbourhood": "Koreatown",
    "suburb": "Manhattan",
    "city_district": "New York County",
    "city": "New York",
    "state": "New York",
    "ISO3166-2-lvl4": "US-NY",
    "postcode": "10118",
    "country": "United States",
    "country_code": "us"
  },
  "boundingbox": [
    "40.7483757",
    "40.7484757"
  ]
}