# Nominatim on Onekey

> 3 endpoints for Nominatim (0 stable, 3 beta), 1 to 5 credits each. Category: Maps, weather & space. One key, one JSON shape.

Base URL: https://api.onekey.dev
Auth: header `x-api-key: <key>`. Call shape: `GET /v1/{platform}/{endpoint}?{params}`.
Every response is `{success, data, metadata, error}`; check `success` first. Cost is in `metadata.credits_charged`. Free when served from cache (0.2 credit for a cached response over 100 KB). Failed and not-found calls are refunded.
Status: stable = verified against the live source; beta = not yet verified, fields may be missing.

Page: https://onekey.dev/platforms/nominatim
Reference (Markdown): https://onekey.dev/docs/api/nominatim.md
All docs: https://onekey.dev/llms.txt

## Canonical fields returned

Unified-schema fields (same names on every platform), with how many of the 3 mapped Nominatim endpoints return each:

- `entity.category` (string): 3
- `entity.description` (string): 3
- `entity.id` (string): 3
- `entity.name` (string): 3
- `place.lat` (number): 3
- `place.lon` (number): 3
- plus 3 platform-specific fields under `ext.`

## Endpoints

### nominatim.lookup

Look up OSM objects by id (e.g. R62422, N123, W456).
- Price: 5 credits per fresh call. Status: beta. Returns: a list.
- Request: `GET https://api.onekey.dev/v1/nominatim/lookup?osm_ids=R62422` with header `x-api-key: YOUR_API_KEY`
- Parameters:
  - `osm_ids` (string, required): Comma-separated OSM ids with type prefix (N/W/R)
- Fields returned: `entity.id`, `entity.name`, `entity.category`, `entity.description`, `place.lat`, `place.lon`, `ext.importance`, `ext.osmType`, `ext.osmId`
- Reference: https://onekey.dev/docs/api/nominatim/lookup.md

### nominatim.reverse

Reverse geocoding of a coordinate to the nearest address.
- Price: 1 credit per fresh call. Status: beta. Returns: one record.
- Request: `GET https://api.onekey.dev/v1/nominatim/reverse?lat=52.52&lon=13.41` with header `x-api-key: YOUR_API_KEY`
- Parameters:
  - `lat` (string, required): Latitude in decimal degrees (-90..90)
  - `lon` (string, required): Longitude in decimal degrees (-180..180)
  - `zoom` (string, optional, default 18): Detail level (3=country .. 18=building)
- Fields returned: `entity.id`, `entity.name`, `entity.category`, `entity.description`, `place.lat`, `place.lon`, `ext.importance`, `ext.osmType`, `ext.osmId`
- Reference: https://onekey.dev/docs/api/nominatim/reverse.md

### nominatim.search

Forward geocoding of a free-text place/address.
- Price: 5 credits per fresh call. Status: beta. Returns: a list.
- Request: `GET https://api.onekey.dev/v1/nominatim/search?q=Berlin` with header `x-api-key: YOUR_API_KEY`
- Parameters:
  - `q` (string, required): Address or place
  - `limit` (string, optional, default 3): Rows (1-10)
- Fields returned: `entity.id`, `entity.name`, `entity.category`, `entity.description`, `place.lat`, `place.lon`, `ext.importance`, `ext.osmType`, `ext.osmId`
- Reference: https://onekey.dev/docs/api/nominatim/search.md

## Sample request

```bash
curl "https://api.onekey.dev/v1/nominatim/reverse?lat=52.52&lon=13.41" \
  -H "x-api-key: YOUR_API_KEY"
```