nominatim.lookup

beta Advanced

Look up OSM objects by id (e.g. R62422, N123, W456).

GET /v1/nominatim/lookup

What you get#

A list of Nominatim results in Onekey's unified shape, in data (an array). An empty array is a normal, successful answer and is charged like any other; a source that reports "nothing found" as an error returns a free 404 not_found instead.

What it costs#

Advanced · 5 credits for a fresh fetch, charged only when it succeeds.
Free when served from cache (0.2 credit for a cached response over 100 KB).
Free if the request is invalid (never charged) or the source fails or reports not found (refunded).

Parameters#

Name	Type	Required	Default	What it is	Constraints
`osm_ids`	string	yes	(required)	Comma-separated OSM ids with type prefix (N/W/R)	max 130 chars; must match `[NWR]\d{1,12}(?:,[NWR]\d{1,12}){0,9}`; trimmed

Request#

curl "https://api.onekey.dev/v1/nominatim/lookup?osm_ids=R62422" \
  -H "x-api-key: YOUR_API_KEY"

Try it

Add your key to run this call right here. No key? Get one free. The key stays in this tab.

Recorded response#

A real Nominatim response, recorded and returned in Onekey's shape. Fields the platform does not provide are null.

json

{
  "success": true,
  "data": [
    {
      "entity": {
        "id": "145306205",
        "name": "Berlin, Deutschland",
        "category": "boundary",
        "description": "administrative"
      },
      "place": {
        "lat": 52.5173885,
        "lon": 13.3951309
      },
      "ext": {
        "importance": 0.8522196536088086,
        "osmType": "relation",
        "osmId": "62422"
      }
    }
  ],
  "metadata": {
    "platform": "nominatim",
    "endpoint": "lookup",
    "cached": false,
    "stale": false,
    "age_s": 0,
    "fetched_at": "2026-01-01T12:00:00+00:00",
    "credits_charged": 5,
    "request_id": "7f3a9c2e5b1d4c8fa2e6d0b9c4f18e37"
  },
  "error": null
}

Field mapping#

How this endpoint's source fields become Onekey's unified schema. Fields the source lacks come back as null.

Source path	Onekey field	Transform
`place_id`	`entity.id`	`toString`
`display_name`	`entity.name`	-
`category`	`entity.category`	-
`type`	`entity.description`	-
`lat`	`place.lat`	`toNumber`
`lon`	`place.lon`	`toNumber`
`importance`	`ext.importance`	`toNumber`
`osm_type`	`ext.osmType`	-
`osm_id`	`ext.osmId`	`toString`

Caching and freshness#

Fresh for about 30 minutes. Repeat calls in that window are served from cache and are free.
Between 30 minutes and 6 hours the cached copy is still served instantly and marked stale: true while Onekey refreshes it in the background.
If the source is down when a refresh is needed, the last copy can be served for up to 1 day more (marked stale).
A "not found" is remembered for 5 minutes and is free.
The cache is shared across all customers, which is what keeps repeat calls cheap.

What can go wrong#

Status	Code	What to do
401	`unauthorized`	Check the `x-api-key` header.
402	`insufficient_credits`	Add credits; your balance must cover the price.
404	`not_found`	Unknown endpoint path.
422	`invalid_params`	Fix the parameters using the table above. Free.
429	`rate_limited`	Wait `Retry-After` seconds, then retry.
502	`upstream_error`	The source failed. Refunded; retry with backoff.

See Errors for the full list and retry guidance.

Status: beta (not yet verified against the live source).