WebSocket (/ws/v1)

The address is ws://<IP>:<port>/ws/v1. No authentication is required, and the client sends nothing.

Server messages

{
  "type": "snapshot",
  "source": { "type": "vmix", "state": "ready", "error": null },
  "devices": [{ "id": "k3m9x2qa", "name": "Camera 1", "program": true, "preview": false }]
}

{ "type": "heartbeat" }

• A snapshot arrives as soon as the connection opens.
• Any change (tally, cameras added, changed or removed, switcher state) sends a full snapshot. A snapshot identical to the last one is not sent.
• A heartbeat arrives every 2 seconds.
• If a connection’s send buffer overflows, the server closes it. After reconnecting, the client receives the latest snapshot.

Client rules

• No message for 6 seconds: show Unknown, close and reconnect.
• After a disconnect, retry every 2 seconds, and immediately when the app or page returns to the foreground. Each reconnect brings a new full snapshot; replace the old state with it.
• If your camera ID is not in the snapshot, show “Camera deleted”.

Example

let ws, watchdog
function connect() {
  ws = new WebSocket(`${base.replace(/^http/, 'ws')}/ws/v1`)
  const alive = () => {
    clearTimeout(watchdog)
    watchdog = setTimeout(lost, 6000)
  }
  const lost = () => {
    ws.onmessage = ws.onclose = null
    ws.close()
    clearTimeout(watchdog)
    show('unknown')
    setTimeout(connect, 2000)
  }
  alive()
  ws.onmessage = (event) => {
    alive()
    const message = JSON.parse(event.data)
    if (message.type === 'snapshot') show(tallyOf(message, deviceId))
  }
  ws.onclose = lost
}
connect()

For tallyOf, see Display rules.