# POST /v1/trace

> Index: https://kartpunkt.se/llms.txt

operationId: `matchTrace`. The roads a GPS trace travelled, with facts.
Tag: `routing`.

A GPS trace or a drawn line matched to the road network: the stretches travelled, with their road references and the facts asked for, summed. Use it for a path already travelled; for the path to travel, use POST /v1/route. It costs one calculation.

## Request

`POST https://api.kartpunkt.se/v1/trace` with `Authorization: Bearer $KARTPUNKT_API_KEY` and `Content-Type: application/json`, from your backend (never browser code: the key would leak, and CORS is not enabled).

Example body:

```json
{
  "points": [
    {
      "lat": 63.71824,
      "lon": 19.423726,
      "time": "2026-10-13T07:00:00.000Z"
    },
    {
      "lat": 63.718058,
      "lon": 19.429781,
      "time": "2026-10-13T07:01:00.000Z"
    },
    {
      "lat": 63.717876,
      "lon": 19.435836,
      "time": "2026-10-13T07:02:00.000Z"
    },
    {
      "lat": 63.717804,
      "lon": 19.437852,
      "time": "2026-10-13T07:03:00.000Z"
    }
  ],
  "profile": "car_shortest",
  "facts": [
    "speed_limit",
    "road_number",
    "traffic_safety_class"
  ]
}
```

JSON body:

- `points` (array of [TracePoint](https://api.kartpunkt.se/docs/shapes/TracePoint.md), 2..2000 items, required)
- `profile` ([Profile](https://api.kartpunkt.se/docs/shapes/Profile.md), optional, default "car_shortest")
- `gps_accuracy_m` (number <= 200, optional, default 20): How far, in metres, a fix may lie from the road it was recorded on.
- `facts` (array of "speed_limit" | "road_owner" | "surface" | "road_class" | "network" | "gcm_type" | "municipality" | "road_name" | "road_number" | "traffic_safety_class" | "built_up" | "lit" | "separated" | "ferry" | "motorway" | "fast_road" | "speed_limit_varies" | "unlit_outside_built_up" | "traffic_volume" | "crossings_without_refuge" | "crossings_unknown_refuge" | "level_crossings" | "max_weight" | "max_axle_load" | "max_height" | "max_width" | "max_length" | "bearing_class" | "hgv_banned" | "hazmat_banned" | "hazmat_route" | "timed_restriction" | "structure" | "barriers", 0..34 items, optional): The facts to report along the path: see GET /v1/facts. None by default.
- `geometry` ("geojson" | "polyline6" | "none", optional, default "geojson"): How lines are returned: GeoJSON, an encoded polyline at 6 decimals, or not at all.
- `network` ([NetworkSelector](https://api.kartpunkt.se/docs/shapes/NetworkSelector.md), optional)

## Response 200

Example:

```json
{
  "status": "ok",
  "distance_m": 700,
  "segments": [
    {
      "length_m": 250,
      "ref": "0:17778@0.166714-1.000000",
      "facts": {
        "speed_limit": "80",
        "road_number": "364",
        "traffic_safety_class": "god"
      },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            19.423726,
            63.718239
          ],
          [
            19.428771,
            63.718084
          ]
        ]
      }
    },
    {
      "length_m": 300,
      "ref": "0:17779@0.000000-1.000000",
      "facts": {
        "speed_limit": "60",
        "road_number": "364",
        "traffic_safety_class": "mindre god"
      },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            19.428771,
            63.718084
          ],
          [
            19.434825,
            63.717898
          ]
        ]
      }
    },
    {
      "length_m": 150,
      "ref": "0:17780@0.000000-0.749966",
      "facts": {
        "speed_limit": "60",
        "road_number": "364",
        "traffic_safety_class": "mindre god"
      },
      "geometry": {
        "type": "LineString",
        "coordinates": [
          [
            19.434825,
            63.717898
          ],
          [
            19.437852,
            63.717804
          ]
        ]
      }
    }
  ],
  "facts": {
    "speed_limit": {
      "60": 450,
      "80": 250
    },
    "road_number": {
      "364": 700
    },
    "traffic_safety_class": {
      "god": 250,
      "mindre god": 450
    }
  },
  "geometry": {
    "type": "LineString",
    "coordinates": [
      [
        19.423726,
        63.718239
      ],
      [
        19.428771,
        63.718084
      ],
      [
        19.434825,
        63.717898
      ],
      [
        19.437852,
        63.717804
      ]
    ]
  },
  "provenance": {
    "synthetic": true,
    "network": {
      "id": "snap_01k7exampleexampleexample0",
      "dataset": "nvdb",
      "source_date": "2026-10-13",
      "built_at": "2026-10-13T07:00:00.000Z",
      "graph": "snap_01k7exampleexampleexample0",
      "profile": "car_shortest",
      "experimental": false
    },
    "sources": [
      {
        "id": "nvdb",
        "name": "Trafikverket, NVDB",
        "licence": "CC0-1.0",
        "attribution": "Vägdata från NVDB, Trafikverket, CC0 1.0",
        "url": "https://creativecommons.org/publicdomain/zero/1.0/",
        "updated": "2026-10-13"
      }
    ]
  }
}
```

- `status` ("ok" | "not_matched"): 'ok' when the trace was matched to the network; 'not_matched' when no path along it was found.
- `distance_m` (number | null): Metres along the network of the path matched; null when not matched.
- `segments` (array of [Segment](https://api.kartpunkt.se/docs/shapes/Segment.md))
- `facts` (object): The facts asked for, over the path matched.
- `geometry` (object | string | null, optional): The whole matched path as one line, in the format asked; null when not matched. Left out with geometry 'none'.
  - `type` ("LineString")
  - `coordinates` (array of array of number)
- `provenance` ([Provenance](https://api.kartpunkt.se/docs/shapes/Provenance.md))

## Errors

Every error is `{ error, message, param?, doc_url }`; `message` says what to do next. All codes: [https://api.kartpunkt.se/errors](https://api.kartpunkt.se/errors). What to do on each, with retries: [https://api.kartpunkt.se/docs/recipes/errors-and-retries.md](https://api.kartpunkt.se/docs/recipes/errors-and-retries.md).

- [`invalid_request`](https://api.kartpunkt.se/errors/invalid_request) (400): The request does not match the API schema. Fix the fields named in this message; see /openapi.json.
- [`unauthorized`](https://api.kartpunkt.se/errors/unauthorized) (401): Missing or unknown API key. Send it as 'Authorization: Bearer <key>' (or 'x-api-key'), read from the KARTPUNKT_API_KEY environment variable. The user creates a kp_test_ key on their Kartpunkt account page (https://kartpunkt.se/konto) and puts it in KARTPUNKT_API_KEY themselves; never ask them to paste a key into chat.
- [`live_access_required`](https://api.kartpunkt.se/errors/live_access_required) (403): This account is not approved for live data: kp_live_ keys are for customers under contract. Use a kp_test_ key. To ask for live access, the account holder writes to hej@kartpunkt.se, or orders a plan at https://kartpunkt.se/konto#plan.
- [`use_not_permitted`](https://api.kartpunkt.se/errors/use_not_permitted) (403): This operation would use a data source in a way its licence or approval does not allow (see GET /v1/sources). It cannot be answered for this key.
- [`network_unavailable`](https://api.kartpunkt.se/errors/network_unavailable) (404): No network snapshot matches that id or as_of. List the snapshots with GET /v1/networks and send one of their ids, or leave network out for the active one.
- [`network_not_active`](https://api.kartpunkt.se/errors/network_not_active) (409): That network snapshot is not the one served now, and answers on another snapshot are computed as jobs. Send the same input to POST /v1/jobs with this operation, then read GET /v1/jobs/{id}.
- [`profile_unavailable`](https://api.kartpunkt.se/errors/profile_unavailable) (409): This profile cannot be answered on the network snapshot asked for: it was built without the data the profile needs (see GET /v1/profiles and the snapshot's manifest at GET /v1/networks/{id}). Use another profile or a newer snapshot.
- [`network_pruned`](https://api.kartpunkt.se/errors/network_pruned) (410): That network snapshot was pruned: its tables and graph are deleted, so nothing can be answered on it again, as a job or otherwise. Leave network out to answer on the active network, and store that answer's provenance.network.id; GET /v1/networks lists the snapshots that are not pruned.
- [`too_large`](https://api.kartpunkt.se/errors/too_large) (413): Too much for one synchronous call. Send the same input to POST /v1/jobs with this operation and read the result from GET /v1/jobs/{id}, or split it.
- [`quota_exceeded`](https://api.kartpunkt.se/errors/quota_exceeded) (429): Request limit or plan quota reached (per minute, per day, or the account plan's monthly quota). Wait the number of seconds in the Retry-After header, then retry; without Retry-After, no wait helps: tell the account holder what this message says.
- [`internal_error`](https://api.kartpunkt.se/errors/internal_error) (500): Something failed on our side. Retry after a few seconds; if it keeps failing, contact hej@kartpunkt.se.
- [`live_data_unavailable`](https://api.kartpunkt.se/errors/live_data_unavailable) (503): Live data is not available yet: it opens when Kartpunkt's import of Lantmäteriet's address register completes. Use a kp_test_ key until then.
- [`routing_unavailable`](https://api.kartpunkt.se/errors/routing_unavailable) (503): Road distances and routes are not available yet: Kartpunkt's road graph from Trafikverket's NVDB has not been built. Try again later.

## Limits

| Limit | Synchronous | As a job (`POST /v1/jobs`, `operation: "trace"`) |
| --- | --- | --- |
| `points` | 2000 | 2000 |
| `gps_accuracy_m` (at most) | 200 | 200 |
| `facts` (items) | 34 | 34 |
| Request body | 1 MB | 8 MB |

Above a synchronous limit the call is refused (413 `too_large`, or 400 `invalid_request` naming the field); send the same input as a job.

## Metering

Calculations: 1 per call.