Users expect instant feedback. Loading spinners are so 2020. Here is how to push data to the client efficiently.
The Scaling Problem
Socket.io works great on a single server. But if you have 10 servers behind a load balancer, User A connected to Server 1 cannot talk to User B connected to Server 2.
Redis Adapter
The solution is the Redis Adapter. When Server 1 receives a message, it publishes it to a Redis channel. All other servers subscribe to that channel and broadcast the message to their local connected clients. This stateless architecture scales horizontally indefinitely.
Handling Disconnects
Real-time isn't just about sending data; it's about presence. implementing "User is Typing" or "Online Status" requires careful heartbeating to avoid zombie connections.
#NodeJS#Redis#WebSockets#SystemDesign