Can we send push notification to APNs from iOS device?

Question

I want to send push notification from a iOS device to another iOS device without using backend server. Is it possible for an iOS device to act like a server and send push notification to APNs server?. Thanks in advance.

Answer 1

Theoretically you can send Apple Push Notifications from a device directly to another device. All you need are the push certificate of the app, the device token of the device you are sending the notification to, and code that establishes a secure TLS connection to the APNS servers.

However, there are several practical problems that make the use of a server almost mandatory :

1. You need a single place where all the device tokens of all the devices that installed your app will be sent to and persisted in. The best such place would be a server. Without a server, how would device A send its device token to other devices that want to send it push notifications?

2. Apple require that you keep connections with the APNS server open for as long as possible and use the same connection for sending many notifications. If you open a connection to APNS server on your device, it will probably be short lived (since devices switch networks frequently, and don't stay connected to the internet all the time). Therefore, if you try to send many notifications frequently, and each time use a new connection to APNS, you will probably be banned (since Apple would treat this as DDoS attack).

3. If you store the push certificate in each device that installs your app (to allow it to send push notifications to other devices directly), aside from the security issue of storing the certificate in many places, you'll have to publish a new version of your app each time the push certificate expires (once a year), and push notifications would stop working for users who don't upgrade to the new version.