Connect the KvK API to your CRM, forms and accounting

What you can do with the KvK API

• Complete a KvK number in your form or CRM with name, address and branches
• Check customers and suppliers for an existing and active KvK number
• Include SBI code and legal form for segmentation and quotes
• Follow changes at customers or suppliers with the KvK Mutatieservice
• Keep trade names and the registered name in line in your accounting

How the integration works

The KvK API works with an API key and an agreement with the KvK. Searching by name, address or number goes through the Search API (Zoeken-API), which is free. The details come from the Basisprofiel or Vestigingsprofiel (basic profile or branch profile), at €0.02 per request, on top of a subscription of €6.40 per month (KvK prices, October 2026). In n8n, an HTTP step talks to the API. I first build against the free KvK test environment with fictitious data, and only then against production.

Facts about the the KvK API API

Checked on 2 November 2026 against the official documentation. Limits, prices and versions change; the source is listed per row.

Fact	What the documentation says	Source
Authentication	API key in the apikey header. Requested through the Developer Portal with a KVK number and an authorised signatory; the connection can take up to seven business days.	KvK: Apply for APIs
Rate limits	No call limit in the documentation; only a result limit of 100 per page for Search.	KvK: Documentation
Webhooks	No. For changes there is a separate Mutation Service as a subscription.	KvK: Pricing
Test environment	Free, without registration: a test environment with a fixed test key and a small set of fictitious companies.	KvK: Testing
Version	Search API v2 (since 29 January 2024), Basic Profile v1 (latest release 20 April 2026), Establishment Profile v1, Naming v1. GET only, in JSON.	KvK: Release notes Search API
Cost	Subscription €6.40 per month; Search free; Basic Profile, Establishment Profile and Naming €0.02 per query; Mutation Service €1,279 per year. Exempt from VAT.	KvK: Pricing
Objects	Search (find a KVK number), Basic Profile (by KVK number), Establishment Profile (by establishment number) and Naming (trade names).	KvK: Documentation
n8n	No built-in node and no community node found; the integration runs through an HTTP step in n8n.	n8n documentation

What you need on your side

• An API subscription with the KvK in your company's name, requested by an authorised signatory
• A fixed place in your CRM or form for the KVK number, as the key for enrichment
• Agreements on what you do with the data; passing it on or reselling it is not allowed under the terms
• A decision on the non-mailing indicator: when that flag is set, the integration blocks direct marketing by post

Where it often goes wrong, and how I prevent it

• Non-mailing indicator: if this flag is set, you may not use the address for direct marketing by post or door to door. The integration takes the flag along and blocks that use.
• Passing data on: the KvK terms of use prohibit reselling or passing on the data. The integration only uses it in your own systems.
• Costs when testing: requests on production are always invoiced, even when they were accidental or for a test. That is why testing happens in the test environment.
• Shielded addresses: you do not get residential addresses or shielded addresses. An empty address is therefore not an error; the integration then asks for manual completion.

In practice

A KvK integration is not yet listed as In production with me. The approach is the same as with my other API integrations: against the test environment first, a fixed key per relation so no duplicates appear, and an alert in plain language when a request fails. For quote requests and onboarding, the KvK number is often the only field the customer has to fill in themselves.

What it costs

I build a KvK API integration as one scoped process for a fixed price, from €750. Maintenance and monitoring are a monthly fee: n8n management from €250 per month, server management €145 per server. You pay the KvK costs (€6.40 per month and €0.02 per profile) directly to the KvK. All prices and what is included →

What I do not do

• I do not query data before your subscription and key are in place; I build against the free test environment until they are.
• I do not store KvK data outside your own systems and do not pass it on.
• I do not perform UBO checks; the UBO register has its own API for a limited group of parties.

Frequently asked questions about the KvK API

What does the KvK API cost?

A subscription costs €6.40 per month. Searching is free; a Basisprofiel, Vestigingsprofiel or Naamgeving costs €0.02 per request. The Mutatieservice costs €1,279 per year extra. Those are the KvK prices in October 2026; building the integration comes on top of that.

Does n8n have a KvK integration?

No, n8n has no built-in KvK node. I build the integration with an HTTP step on the KvK API. For this, the KvK publishes an OpenAPI specification and a free test environment with fictitious data.

Can I do a UBO check with the KvK API?

Not with the regular KvK API. The UBO register has its own API for banks, notaries, trust offices and certain financial institutions. For a firm, an integration can prepare the data from the Basisprofiel for a Wwft (Dutch anti-money laundering act) file; the judgement stays with you.

How long does it take before I can use the KvK API?

The KvK mentions up to seven business days for the connection, after a request by an authorised signatory of your company. In the meantime I build against the free test environment with fictitious data, so the integration is ready as soon as the key arrives.

May I use a KvK address for a mailing?

Not always. When the non-mailing indicator is set, you may not use the address for direct marketing by post or door to door. The integration carries that flag into your CRM and blocks that use.