API changelog

Every change to the Motorbay API that you can see, newest first.

How we version the API

The major version is in the URL: /v1. Within /v1, changes only add things: new endpoints, fields, parameters, enum values and error codes. A breaking change comes as a new version, such as /v2. We announce it here at least 30 days ahead, as the terms promise. The old version keeps running for at least six months after its successor ships. Deprecated endpoints and fields are marked deprecated in the API reference.

28 Sep 2026

Timestamps are in UTC. Every timestamp, meaning fields ending in At and importedAt on /v1/dataset, is sent in UTC with a Z, for example 2026-09-18T08:43:12.345Z. Before, some carried +02:00. The instant is the same.
Reference data names are Motorstyrelsen's text. The name field on reference data is Motorstyrelsen's Danish text, the same as originalName.

26 Sep 2026

503 when your key can't be checked. When your API key can't be checked for a moment, the API answers 503 with the code ServiceUnavailable and a Retry-After header, not 401. Your key is fine: retry after the given number of seconds.
HEAD /health/data. GET /health/data also answers HEAD, for uptime monitors that only send HEAD.

25 Sep 2026

Plate lookup normalizes its input. GET /v1/vehicles/plate/{plate} trims, uppercases and removes spaces and hyphens, so ab 12 345 finds AB12345. Input with characters other than A to Z, 0 to 9, Æ, Ø and Å, or longer than 10, is a 400 with the new rule code RegistrationNumberInvalid.
Plate lookup picks the right vehicle. When several vehicles have had a registration number, the lookup returns the one currently registered with it, or else the most recent one. The answer no longer changes between requests.
Search by registration number. GET /v1/vehicles?registrationNumber= lists every vehicle that has had a registration number, in the order the lookup picks from.

24 Sep 2026

The first version of the API, /v1.

Vehicles by ID, VIN and registration number, with their technical details, engine, environmental information, inspection, equipment and secondary usages.
Vehicle search with filters on make, kind, usage, color and model year, sorting with sortBy, and at most 10,000 results per search.
Reference data: makes, models, variants, designation types, colors, kinds, usages, emission standards and equipment.
GET /v1/dataset and the Motorbay-Data-As-Of header, to see how old the data is.
Authentication with the X-Api-Key header.
Errors as problem details with a stable code, and an X-Request-Id header on every response.
60 requests per minute per key.

How we version the API

28 Sep 2026

Timestamps are in UTC. Every timestamp, meaning fields ending in At and importedAt on /v1/dataset, is sent in UTC with a Z, for example 2026-09-18T08:43:12.345Z. Before, some carried +02:00. The instant is the same.

Reference data names are Motorstyrelsen's text. The name field on reference data is Motorstyrelsen's Danish text, the same as originalName.

26 Sep 2026

503 when your key can't be checked. When your API key can't be checked for a moment, the API answers 503 with the code ServiceUnavailable and a Retry-After header, not 401. Your key is fine: retry after the given number of seconds.

HEAD /health/data. GET /health/data also answers HEAD, for uptime monitors that only send HEAD.

25 Sep 2026

Plate lookup normalizes its input. GET /v1/vehicles/plate/{plate} trims, uppercases and removes spaces and hyphens, so ab 12 345 finds AB12345. Input with characters other than A to Z, 0 to 9, Æ, Ø and Å, or longer than 10, is a 400 with the new rule code RegistrationNumberInvalid.

Plate lookup picks the right vehicle. When several vehicles have had a registration number, the lookup returns the one currently registered with it, or else the most recent one. The answer no longer changes between requests.

Search by registration number. GET /v1/vehicles?registrationNumber= lists every vehicle that has had a registration number, in the order the lookup picks from.

24 Sep 2026

The first version of the API, /v1.

Vehicles by ID, VIN and registration number, with their technical details, engine, environmental information, inspection, equipment and secondary usages.

Vehicle search with filters on make, kind, usage, color and model year, sorting with sortBy, and at most 10,000 results per search.

Reference data: makes, models, variants, designation types, colors, kinds, usages, emission standards and equipment.

GET /v1/dataset and the Motorbay-Data-As-Of header, to see how old the data is.

Authentication with the X-Api-Key header.

Errors as problem details with a stable code, and an X-Request-Id header on every response.

60 requests per minute per key.