The upgrade handshake, plus an optional round-trip: send a frame and match the reply.
Every WebSocket monitor runs on the same spine as the rest of PulseTrace — probed from each region you pick, scored on every check, and streamed into one timeline where incidents open on their own, anomalies surface without a threshold to guess, and reports are generated for you. Point it at a target, choose an interval, and it's watched.
What each check verifies
The panel on the right is the real create-monitor screen — it fills itself in with a WebSocket example, exactly what you'd type.
For real-time endpoints — chat, live dashboards, collaborative editing, trading feeds — where the HTTP handshake succeeding says nothing about whether the socket stays open and answers. It connects, optionally sends a message, and asserts on the reply.
wss://live.example.com/socket is DOWN — upgrade succeeded but no message received within 5 s (eu, us-east).