WebSocket over SCDN: from successful handshake to stable sessions
Chat, notifications and collaboration need tests for heartbeats, idle timeouts and reconnects.
Contents of this article
A persistent session differs from a page request
WebSocket exchanges messages bidirectionally after connection establishment. Choose a supporting plan and confirm the endpoint, TLS and origin service. A working page does not prove that the message channel works.
Validate heartbeat and idle behavior
Check heartbeats, proxy idle timeouts and origin connection management for quiet sessions. Do not mask timeout mismatches with excessively frequent heartbeats, which add traffic and device cost.
Verify message consistency after reconnecting
Network changes and releases can interrupt sessions. Handle reauthentication, replay of missed messages and duplicates. Check session membership and permissions after reconnecting rather than blindly reusing old connection state.
Size for active connections, not page views
Measure simultaneous sessions, messages per connection and normal disconnect rates against plan limits. Include idle sessions, mobile-network changes and backend restarts in validation.
References
NGINX HTTP proxy documentation