bitFlyer Lightning Realtime API Playground
The Realtime API can provide information after the point of connection establishment. If the connection is lost, information delivered before reconnection can not be received. (Connection may be intentionaly disconnected for maintenance.)
Sample codes for JSON-RPC 2.0 over WebSocket do not include reconection procedure. You need to implement it to receive continuosly.
TLS 1.2 compatible client and client settings are required to connect.
For HTTP API, see API Playground.