Is there an official WOZ API for companies?

Not for commercial use. The official WOZ API Bevragen from Kadaster is restricted to municipalities and requires a Dutch government organisation number (OIN) and a PKIoverheid certificate. The public WOZ-waardeloket is a lookup website without an API and does not allow bulk extraction. Commercial APIs such as WozApi are the practical route.

What does the WozApi WOZ value API cost?

You pay per unique address. One credit is one unique address, starting at EUR 0,35 excluding VAT and dropping with volume. Requesting the same address again within 7 days is free. A new account gets 10 free credits, no credit card required.

For developers outside the Netherlands

WOZ value API for Dutch properties

Get the official Dutch WOZ property value, BAG address data and cadastral parcels for any Dutch address in a single JSON response. Self-serve: create an account, generate a key and make your first call in minutes.

Price per address: € 0,35
Billing unit: 1 credit = 1 unique address
Repeat lookups: free for 7 days
To get started: 10 free credits

Create a free account Read the API docs

Liever Nederlands? Bekijk de Nederlandse versie.

What is the WOZ value?

The WOZ value (Waardering Onroerende Zaken) is the official property value that every Dutch municipality determines annually for every property. It drives property tax, part of income tax and the water authority levy, which makes it the closest thing the Netherlands has to an official valuation of a home.

Two things matter when you build on it. First, the value lags: a 2026 WOZ value has a reference date of 1 January 2025, so it reflects the market a year earlier. Second, only residential properties are published openly; commercial properties are not.

Curious how these values develop across the country? We publish the average WOZ value per province and municipality from open CBS data, including a downloadable dataset.

Is there an official WOZ API?

Short answer: not one you can use commercially.

Routes to Dutch WOZ data
Route	Who can use it	What it takes
WOZ API Bevragen (Kadaster)	Dutch municipalities only	OIN plus PKIoverheid certificate
WOZ-waardeloket	Anyone, one address at a time	No API, bulk extraction not permitted
WozApi	Developers and data teams	Sign up, get 10 free credits, call the API

One call, three registries

WOZ values for every available reference date, so you get the history and not just the latest figure.
BAG address data: the official Dutch registry of addresses and buildings, including construction year and surface area.
Cadastral parcels with surface area, and parcel boundaries as GeoJSON when you ask for them.

Client libraries for Python, Node.js and .NET are available in our repository, and the full reference lives in the Swagger documentation. No developer on the team? The Excel wizard enriches a spreadsheet of addresses without writing any code.

Try it with your own addresses

A free account comes with 10 credits. No credit card, no sales call.

Create a free account See pricing