{
  "jsonrpc": "2.0",
  "method": "public/subscribe",
  "id": 42,
  "params": {
    "channels": [
      "deribit_volatility_index.(index_name)"
    ]
  }
}

{
  "data": {
    "volatility": 129.36,
    "timestamp": 1619777946007,
    "index_name": "btc_usd"
  }
}