1) internet connection is available
2) that the neucard site is up and working
so it is in some ways an IOT of sorts, right?
For the NFC those two conditions are of course needed, but for the app, is there a "local cache" of contacts in case either of the two conditions are not met?
Or are these contacts automatically added[1] to the phone contacts?
And how does the updating works?
I mean, does the app "phone home" periodically or only when you ask for a given contact (or both)?
[1] even if in a possibly outdated version
As for adding info to the phone contacts, this is a tricky situation. Right now, I do not sync the contact info from received cards into the contacts on the phone. This is because the contacts on the phone are a shared resource that other apps can access, and I don't want people's contact info to leak. I do support caller identification, so you will see a person's name rather than just a number when they call for all of the numbers on your received cards. But, this isn't as robust of an experience as having all the info in the phone's contacts.
Maybe you could do the reverse, i.e. somehow allow the neucard app to "import" the standard contacts, if this would be possible, the neucard app could double as a "private contacts app" that might have more general use.