API documentation

The purpose of feedback

Even though we use multiple (official) data sources to arrive at an up-to-date database, there is the possibility to add your own addresses that will be immediately available for your account in the supplement API.

The gamerules

To be able to use this method, you must have included such a text in your privacy statement or general conditions in accordance with the Personal Data Protection Act (Wbp):

"Webshop XYZ will not sell your personal information to third parties and will only make it available to third parties that are involved in processing your order.

Instead of the above text, an explicit opt-in after the customer has entered the address details is also sufficient.

Example code feedback method

The use of this method as an example in different languages:

We encourage you to request example code in the language you prefer. In the meantime, you might want to look at the autocomplete method, which is already demonstrated in many languages.


Even though we use multiple (official) data sources to come up with an up-to-date database, there are available own addresses and become available immediately for your account in the supplement API.

Required parameters

  • nl_sixpp: enter the postcode.
  • street: enter the street.
  • streetnumber: enter the house number.

Optional parameters

  • extension: Specify the house number addition.
  • claim: geef een reden op.

Result example


This request gives the following result:

  "status": "ok",
  "results": []

More examples of the feedback method.

Error messages

  • Parameter nl_sixpp is required
    Provide the "nl_sixpp" parameter to the web service. This is allowed both in the URL (GET) and in the body (POST).
  • Invalid nl_sixpp format
    The format must consist of 4 digits and 2 letters. Extra spacing and the use of upper or lower case letters are automatically corrected.