Not a REST call: this is the WebSocket handshake. Connect to the URL below and the exchange answers 101 Switching Protocols; everything after that is frames, not requests.

Public: no key, no signature.

Futures candles as they update. Params contains the futures pair code and the period in seconds:

{ "Method": "subscribe", "Params": ["BTCUSDT", 60] }

Valid periodSeconds values are 60, 180, 300, 900, 1800, 3600, 14400, 28800, 86400, 604800, and 2592000 — the same CandleTimePeriod accepted by GET /api/futures/exchange-data/candles.

{
  "currencyPairCode": "BTCUSDT",
  "openPrice": 64100.0,
  "closePrice": 64180.5,
  "maxPrice": 64210.0,
  "minPrice": 64080.0,
  "candleTimePeriod": 60,
  "volume": 125000.0,
  "volumeBase": 1.95,
  "openTimestamp": "2026-09-21T09:15:00Z",
  "closeTimestamp": "2026-09-21T09:16:00Z"
}

Pair codes have no underscore. A missing or invalid parameter gets {"Error":"Invalid parameters"}; /ping is shared.