Nominatim — Free OpenStreetMap Geocoding API (No Key)

TL;DR

Nominatim is OpenStreetMap's free geocoding engine. Forward geocode an address or place name to get GPS coordinates (lat/lon), or reverse geocode coordinates to get a structured address. Covers the entire world using community-maintained OpenStreetMap data. Returns JSON, XML, or GeoJSON. Requires a User-Agent header identifying your application. Max 1 request per second.

Quick start: https://nominatim.openstreetmap.org/search?q=London&format=json&limit=1

No API key needed — free global geocoding!

How to Use This API

1. Forward Geocode — Address to Coordinates

Convert a place name to GPS coordinates (always include a User-Agent header):

https://nominatim.openstreetmap.org/search?q=London&format=json&limit=1

2. Reverse Geocode — Coordinates to Address

https://nominatim.openstreetmap.org/reverse?lat=51.5074&lon=-0.1278&format=json

3. Search with Country Filter

https://nominatim.openstreetmap.org/search?q=Springfield&countrycodes=US&format=json

4. JavaScript — Geocode with Headers

fetch('https://nominatim.openstreetmap.org/search?q=Paris&format=json&limit=3', {
  headers: {'User-Agent': 'MyApp/1.0 (contact@example.com)'}
})
  .then(r => r.json())
  .then(data => {
    data.forEach(place => {
      console.log(place.display_name);
      console.log(`  Lat: ${place.lat}, Lon: ${place.lon}`);
      console.log(`  Type: ${place.type}`);
    });
  });

5. Python — Structured Address Search

import requests

headers = {'User-Agent': 'MyGeocodingApp/1.0'}
params = {
    'city': 'Berlin',
    'street': 'Unter den Linden',
    'countrycodes': 'DE',
    'format': 'json',
    'limit': 1
}
resp = requests.get(
    'https://nominatim.openstreetmap.org/search',
    params=params, headers=headers
).json()

if resp:
    p = resp[0]
    print(f"{p['display_name']}")
    print(f"GPS: {p['lat']}, {p['lon']}")
    print(f"Importance: {p['importance']}")

Search "London": https://nominatim.openstreetmap.org/search?q=London&format=json&limit=1

Try This URL Now

Frequently Asked Questions

Why do I need a User-Agent header?: Nominatim requires a User-Agent header so they can contact you if your app causes problems. Include your app name and a contact email or URL. Requests without a User-Agent may be blocked.
What is the rate limit?: Max 1 request per second. This is strictly enforced. For higher volumes, you can self-host Nominatim or use a commercial geocoding provider. Use caching to reduce duplicate requests.
What output formats are supported?: format=json (JSON v2), format=xml, format=jsonv2 (extended JSON), format=geojson, or format=html (debug view). JSON is recommended for most applications.
Can I search by specific address components?: Yes — use structured parameters: street, city, county, state, country, postalcode. Combine with countrycodes to narrow results.
What data is returned for each result?: display_name (full formatted address), lat/lon, type (administrative, building, amenity, etc.), importance (relevance score), osm_type/osm_id, and address breakdown in JSON v2.
Does the reverse geocoding include POI data?: Yes — /reverse returns the nearest OSM element, which could be a building, street, address point, or point of interest. Add zoom=18 for building-level precision.

API Details

API URL: https://nominatim.openstreetmap.org/
Documentation: nominatim.org
Category: Geocoding
Authentication: Not Required (User-Agent header required)
Rate Limit: 1 request per second

What You Can Build

Location search for any mapping or navigation application
Delivery address autocomplete and validation for e-commerce
Reverse geocoding to convert GPS coordinates to human addresses
Travel planner with geocoded points of interest
Address normalization for CRM or logistics systems