I have a KNX system in my house, but the programmer has never tried to use Nuki. Checking your site (address How to: connect Nuki with KNX Smart Home - Nuki) it seems that Nuki cannot be used with KNX . Is the situation still the same as in 2020 or is it now possible to use your APIs to manage the opening and closing of ports via IP or web?
There actually is, it is called Home Assistant and is a 3rd party system you should have anyway when you use KNX. Problem is that the Nuki will not tell you its IP, and the provided explanation by the NUKI TEAM here is simply not working, which, unfortunately, bring us back to the worst thing about Nukis: The support is unbelievably bad.
Google list several different options if you search for “Nuki KNX”.