Just in case anyone else runs into this problem, here's what I found... Using the StoreKit configuration that is provided in Xcode, you can test subscriptions in the simulator with no problems. However, trying to connect to the store and pull down IAP products on the simulator DOES NOT work. Switching to a physical device, it will quite happily pull down in-app purchases even though the app itself has not been submitted for approval.

Thank you for your amazingly detailed reply. TBH, I've never really kept up with the advances in the Network framework (all my day-to-day dev work so far has been invoking standard REST APIs using URLSession), so I kinda assumed it was just a newer version of CFNetwork which seemed pretty low level for my needs. After watching the videos you linked me too and had a look through the sample project, it very much seems like I can get a loooong way with the Network framework - stuff like the protocol framing looks really neat and relevant. I'll definition be starting there for some of my early prototyping. Thanks so much. One quick sidebar: ... as it's VERY difficult (basically, impossible*) to establish reliable connections between "everyone" on the internet The good news for me is that fully remote connections is actually an anti-goal for my game... my idea here is actually that this game is designed around the idea that players are physically co-located in the same room... which should remove (hopefully) a lot of the technical networking hurdles. Thanks again