Will communication specifications from iOS devices to APNs need to be communicated directly without going through the proxy server?
To start, it’s not a proxy server but a provider. And yes, you will need one. It’s not practical for your iOS app to talk to APNs directly because:
APNs uses TLS client certificate authentication to authorise each connection. For that to work the client must have a APNs digital identity issued by Apple (a digital identity includes a certificate and the private key that matches the public key in that certificate). You can’t put that digital identity in your iOS app for all sorts of reasons, not least of which is that someone could extract it from your app and then connect to APNs as you!
APNs has a denial of service check, and if a bazillion copies of your app all connect to APNs at once it’s going to trip that.
If you’re interested in generating push notifications without any server infrastructure, one option is CloudKit.
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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
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