Thanks again Quinn. I'll have a look into CloudKit, and see if I can get it working in my App. I'll feed back to you once In know.

Hi Quinn, I feel you were gently guiding me towards GameKit and the Game Center, so I did some research to see if I could go this route. The good news is that Game Center does EVERYTHING I need, (Send/receive of data, Push Notifications, find and invite friends, nearby users, etc, etc, etc...). BUT My app is not a game. If I could hide all the Game Center parts, we would be good to go. I know I can change the Notifications, and ViewControllers, but the users will still be forced to have a Game Center account and log into it. I feel that Game Center is an unnecessary distraction for my users. Is there an alternative, simply using the Apple Sign In? That would be awesome. Thanks again.

Thanks Quinn for the explanation. It all makes sense. My app is not a game, but in simple terms it requires one user to send a small amount of data to another user (possibly remote), on a regular basis (maybe every 5-10 seconds?). I have a working prototype which uses Google Firebase to transfer this data via "documents" in an online database, but of course this has an associated cost. My hopes were that a socket (or some other mechanism) could provide this functionality for free. The solution doesn't have to be serverless, but should be as cost free as possible.

Thanks

Hi Quinn You could be right on the misunderstanding of modern networking. I wrote my first socket code in early 1990s. But for this app I'm keen to use the most up-to-date solution possible. Yes. Apple platforms only. Yes. Two separate users... Yes. Two separate devices... which could be in completely different continents. My app doesn't really justify TCP so I chose UDP (for speed, and because TCP ended up needing an NWProtocolFramer due to it combining multiple messages together.) Currently I am only targeting iOS.