Blog92.3K views4,094 votes0 replies652 following
Socket.IO Rooms Stay Local Until You Add an Adapter
Socket.IO rooms broadcast only within one Node process. Learn when to add the Redis adapter and verify cross-node delivery.
Loading…
ReadMeFeed / Community knowledge
Real questions. Useful conversations. Find the people who know your stack.
Socket.IO rooms broadcast only within one Node process. Learn when to add the Redis adapter and verify cross-node delivery.
Socket.IO rooms are local to one server process. Learn when to add the Redis adapter for multi-node broadcasts.
Learn how to horizontally scale Socket.IO with the Redis adapter: minimal code, NGINX sticky sessions, verification commands, and the operational trade‑offs you’ll face in production.
Socket.io is stateful, so scaling beyond one process requires choosing between the in-process Memory Adapter and the Redis Adapter for cross-node broadcast. This guide compares the options and shows how to validate a Redis-backed deployment.
I'm planning a zero-downtime migration of a small Socket.IO application to a multi-node setup behind a load balancer. During rolling restarts, clients using the default transports can hit the Engine.IO error Session ID unknown (HTTP 400), because the handshake session lives in memory on the node that issued it and a subsequent polling request may land on a d
I'm designing a repeatable development setup for a Socket.IO application (Node.js, socket.io 4.x) and trying to pin down the exact limits of connection state recovery before committing to an architecture. My understanding is that connectionStateRecovery is enabled by default and lets a client resume its session within maxDisconnectionDuration (default two mi
Context A small Socket.IO application runs on a single Node.js process behind a load balancer. The team plans a rolling deployment to a new version across two nodes without dropping active clients. The constraint is zero downtime for WebSocket and HTTP long-polling transports during the cutover window. Trade-off Sticky sessions (session affinity) keep each c
Goal I want clients that briefly lose connectivity to receive the events they missed and keep their room memberships after reconnecting, even if the Socket.IO server process restarts during the outage. Context and constraints Assume Socket.IO v4.6+ on both server and client, with connectionStateRecovery enabled and a configured maxDisconnectionDuration . As
nodejs
socketio