mids

{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "subscribe",
  "params": {
    "channel": "mids",
    "symbol": "BTC-PERP"  // support "all"
  }
}

{
    "jsonrpc": "2.0",
    "method": "event",
    "params": {
        "channel": "mids:BTC-PERP",
        "data": {
            "symbol": "BTC-PERP",
            "mid_price": 67887
        }
    }
}

import websocket
import json

def on_message(ws, message):
    print(f"Received: {message}")

def on_open(ws):
    subscribe_msg = {
        "jsonrpc": "2.0",
        "id": "1",
        "method": "subscribe",
        "params": {
            "channel": "mids",
            "symbol": "BTC-PERP"  # or "all"
        }
    }
    ws.send(json.dumps(subscribe_msg))

ws = websocket.WebSocketApp("wss://api.hotstuff.trade/ws",
                          on_message=on_message,
                          on_open=on_open)
ws.run_forever()

const ws = new WebSocket('wss://api.hotstuff.trade/ws');

ws.onopen = function() {
    const subscribeMsg = {
        "jsonrpc": "2.0",
        "id": "1",
        "method": "subscribe",
        "params": {
            "channel": "mids",
            "symbol": "BTC-PERP"  // or "all"
        }
    };
    ws.send(JSON.stringify(subscribeMsg));
};

ws.onmessage = function(event) {
    console.log('Received:', event.data);
};