Question 1

What is Nominatim?

Accepted Answer

Nominatim is a geocoding engine that turns addresses into coordinates (forward geocoding) and coordinates into addresses (reverse geocoding), using OpenStreetMap data. It's the same software behind search on OpenStreetMap.org, run here on your own server. It exposes a standard HTTP API — /search for addresses to coordinates and /reverse for the other direction — both returning JSON.

Question 2

Which port does it use and how do I query it?

Accepted Answer

Nominatim runs on host port 8318, mapped from the container's 8080. After the region imports, query it over HTTP — for example http://your-server:8318/search?q=an+address&format=json to geocode an address, or the /reverse endpoint with coordinates. Note the host port is 8318, not the container's 8080. For public use, put a reverse proxy with TLS in front and rate-limit it.

Question 3

Does it need a region imported like a tile server?

Accepted Answer

Yes — Nominatim imports OpenStreetMap data for a Geofabrik region on first run, defaulting to Monaco for a quick test, configurable to any country or continent. Only addresses within the imported region can be geocoded, so import the area your app covers. The import is the heavy step: small regions are quick, large ones need significant RAM and disk and take much longer.

Question 4

Why is the first start slow?

Accepted Answer

On first run Nominatim imports and indexes the region's OpenStreetMap data into its database, which is genuinely heavy processing. A small region like Monaco finishes in minutes, but a large country can take much longer and use a lot of RAM. Watch the container logs to follow the import — a first start that appears stuck is almost always the import working, not a failure.

Question 5

How does it fit with a tile server and GraphHopper?

Accepted Answer

They form a complete self-hosted maps stack. The OSM tile server draws the map, Nominatim provides geocoding (address search and reverse geocoding), and GraphHopper provides routing (directions). Together they replace the display, search, and directions of a commercial map platform like Google Maps, all on your own servers using OpenStreetMap data, with no per-request billing.

🗺️ Setup Nominatim — Self-Hosted Geocoding

📦 Resources & Setup Scripts

Quick Install:

Tutorial Steps

1 Download the Script

2 Make it Executable

3 Run the Installer

4 Query the Geocoding API

Ports Used

Overview

Why Use It

When You Need It

Who Should Use It

Real Use Cases

Main Features

How to Use After Installation

Security Best Practices

Ports and Firewall Notes

Backup and Maintenance

Common Mistakes

Troubleshooting

Alternatives

When Not to Use It

PrismaTechWork Professional Help

Frequently Asked Questions