WebSocket Deep Dive

HTTP asks and waits. WebSockets hold the line open — a true duplex channel where the server is free to speak first.

Scaling the Socket

A single node handles thousands of connections happily. The interesting problems start when you need many nodes to feel like one.

• Sticky routing vs. shared state: pin a client to a node, or make every node stateless behind a shared backplane.
• Redis pub/sub: the pragmatic backplane — publish an event once and every subscribed node fans it out to its own clients.
• Backpressure: a slow client must never stall the broadcast; queue, coalesce, or drop deliberately.

Get those three right and horizontal scaling becomes a config change, not a rewrite.