How does message ordering work in WebSockets?

WebSocket guarantees in-order message delivery over a single connection — messages sent by one party arrive at the other in the exact order they were sent. This is because WebSocket runs over TCP, which guarantees ordered delivery. However, ordering guarantees break in several scenarios: (1) Multiple connections — a user with multiple browser tabs has separate connections; messages from different tabs may interleave on the server; (2) Reconnection — after a disconnect, messages sent during the gap are lost (unless queued); new messages after reconnection arrive, but there's a gap; (3) Multi-server — in a horizontally scaled setup, messages from different server instances broadcast via Redis may arrive in a different order than sent due to network timing. For strict ordering in distributed systems, use sequence numbers or vector clocks to detect and handle out-of-order delivery.