{
  "jsonrpc": "2.0",
  "method": "public/subscribe",
  "id": 42,
  "params": {
    "channels": [
      "quote.BTC-PERPETUAL"
    ]
  }
}

{
  "data": {
    "best_ask_amount": 50,
    "best_ask_price": 3996.61,
    "best_bid_amount": 40,
    "best_bid_price": 3914.97,
    "instrument_name": "BTC-PERPETUAL",
    "timestamp": 1550658624149
  }
}