Master-Class: Sending Real-Time Updates from Server to Clients: Server to Server, Android, iOS

Real-time communication is now a cornerstone of modern software. Whether you're showing live scores, streaming AI responses, pushing a payment confirmation to a phone, or propagating an event between two microservices — the underlying question is the same: how does the server reach the client before the client asks? The answer looks very different depending on who the client is. A backend server, an Android device, and an iPhone each live in fundamentally different environments, face different c