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.

Candles as they update. This channel takes exactly two positional Params — pair, then range:

{ "Method": "subscribe", "Params": ["BTC_USDT", 5] }

Ranges: 1 year, 2 month, 3 day, 4 four hours, 5 hour, 6 30 minutes, 7 15 minutes, 8 5 minutes, 9 3 minutes, 10 one minute.

A frame missing either parameter is answered {"Error":"Invalid parameters"}.