Getting Started with KVKBase

KVKBase provides a simple, fast API for looking up Dutch company data. Get KVK numbers, addresses, VAT validation, and more in a single API call.

1. Sign up for an account

Create a free account at kvkbase.nl/signup. The free plan includes 100 lookups per month — no credit card required.

2. Get your API key

After signing in, go to your Dashboard → API Keys and create a new key. Your key will look like this: 

kvk_live_a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6

Important: Store your API key securely. You won't be able to view it again after creation.

3. Make your first request

Use the /v1/lookup endpoint to fetch company data by KVK number: 

## Look up a company by KVK number
curl https://api.kvkbase.nl/v1/lookup/12345678 \
  -H "Authorization: Bearer YOUR_API_KEY"

You'll get a JSON response like this:

{
  "kvkNumber": "12345678",
  "name": "Acme B.V.",
  "address": {
    "street": "Herengracht 100",
    "city": "Amsterdam",
    "postalCode": "1015 AA"
  },
  "vatNumber": "NL123456789B01",
  "vatValid": true,
  "isActive": true
}

4. Try the widget

Want to add auto-complete to your checkout or registration form? Add the KVKBase widget with just one line of HTML: 

<script
  src="https://widget.kvkbase.nl/v1/widget.js"
  data-apikey="YOUR_API_KEY"
  data-target="#kvk-input"
  data-autofill="true"
></script>

See the Widget documentation for full configuration options.

Next steps