Hello Wessel,
I'm sorry, but I don't think follow. Could you give me more details on how you are working with this URL? Are you creating it using macro, or are you accessing it and want to read its value using macro?
When it comes to URLs, the "214" in this case would be the document name:
producten/detail/
214?productguid=1b1c351a-545b-4408-8896-f24407069f77
In the first post you said the Node parameter that you want to get is also "214". Does that mean the document name and the Node that you want to get is the same?
You can access the DocumentName like this:
{% CurrentDocument.DocumentName %}
Regards,
Josef