The official KVK API or KVKBase

We sit on the same source

There is no second Dutch Business Register. The KVK is the source of record, we query that API ourselves, and every field we return comes from there or from VIES. So the question is not whose data is better, it is who does the assembly work.

A longer technical version of the same comparison lives in the post on the official KVK API versus KVKBase.

What the KVK API does better

Three things, plainly.

It is the authority. In a dispute, an audit or a conversation with a regulator, “fetched from the KVK API” is a stronger answer than “fetched from an intermediary that queries the KVK”. If that is your situation, it outweighs convenience.

There are endpoints we do not resell. Our catalogue is a selection. If you need something outside it, going direct is the only route.

No middleman. A large in-house team that wants its own contract, its own SLA and a direct line during an outage should not put anyone in between. That is a legitimate architectural choice, not a lack of trust.

What going direct actually costs

Not the EUR 0.02. The bill arrives as code.

A complete picture of a company is several calls at the KVK: search to get from a name to a KVK number, the basic profile, the branch profile for address and establishment data, and naming for statutory and trading names. Those are separate responses that you merge yourself, with your own error handling per call and your own decision about what happens when call three fails after one and two succeeded.

Then there is VAT. The VAT number is not in the Business Register. You derive it as NL + KVK number + B01, which only holds for BV and NV, and then you check it against VIES. VIES is SOAP, it is frequently slow, and it goes offline per member state independently. That means retries, a cache, and an explicit answer to the question of what you show when VIES says nothing rather than “invalid”. That last one is the gotcha most integrations break on: valid: false and “VIES was unreachable” must never look the same in your UI.

With us it is one call. GET /v1/lookup/{kvkNumber} returns the profile plus vat with number, valid and validatedAt, and ?enrich=true adds postal address, employee counts, websites, statutory name, trading names and the branch count.

Doing the volume maths

On the paid profile endpoint, a thousand queries lands around EUR 26.40 per month at the KVK, against EUR 19 with us for a thousand lookups. Five thousand comes to roughly EUR 106.40 against our EUR 49. That only flips when you can serve enough from the free search endpoint to keep profile queries low, or when you cache so aggressively that your query count sits far below your user count.

Run the numbers with your own cache hit rate before deciding on price. With a well populated cache of your own, going direct is often cheaper than it first looks.

Who should go direct

Integrate with the KVK directly if you have an in-house team that will carry it, if you want your own contract with the source, or if you need endpoints outside our catalogue. Also go direct for any check where a day of lag is unacceptable, for example an insolvency check just before shipping, where our 24 hour cache is the wrong tool.

If you end up with us, it is because you want company and VAT in one response and would rather not maintain the merge and VIES work yourself.