Frequently asked questions

Where does the data come from?

From 16 datasets of RDW’s open data. We check several times a day whether a new version has been published, and process it. Each response states per dataset when RDW published it (source_published_at) and when we last checked (last_checked_at).

Do I see every change to a vehicle?

You see every difference between two successive versions of the open data that we processed. RDW usually publishes a dataset daily; when a value changes more than once between two versions, you see only the result. A change is in the feed after RDW has published it and we have processed the new version, not at the moment something happened in the real world.

Can I try KentekenFeed for free?

The demo on the home page works without an account, and creating an account is free. For API requests with a key of your own you need a plan or pay as you go, which you activate in the portal with a payment method. Pay as you go has no fixed fee; what is included per month and what a lookup costs after that is on the plans page.

What happens when my allowance runs out?

Above the included number of lookups you pay per extra lookup, up to the maximum of your plan. Once that maximum is reached, the API answers 429 usage_cap_reached until the next calendar month starts. Analytics queries stop at their own maximum with 429 query_cap_reached. The numbers and prices per plan are on the plans page.

What is the difference between a snapshot and a mutation file?

A snapshot is the whole register at one moment, as files per dataset: it is how you start a copy of your own. A mutation file holds only the changes of one day or between two cursors, the same records as the feed: it is how you keep that copy current.

Does it contain owner details?

No. RDW’s open data has no names or addresses of owners or keepers, so neither does KentekenFeed.

What counts as a lookup?

Every successful response to GET /vehicles/{registration}, including those served from our cache. Invalid and unknown registrations, refused requests and outages don’t count. A request you repeat counts again.

What if a dataset is out of date?

You still get the data, with stale: true on every dataset not checked in the last 36 hours, so you decide what to do with it.

What do appeared and disappeared mean?

That a row was added to or removed from RDW’s open dataset. They are not registration or deregistration events: RDW publishes no time per change. Dates such as registration_date are in the change itself.

Can I use several API keys?

Yes, for example one per application, each with only the access it needs. When you replace a key, the old one can keep working for up to 7 days.