NegotiationResponse - Kraken Developers

Confirms a successful negotiation, with the agreed keepalive interval and the session expiry time. Direction: Kraken → client

ID	Field	Type	Encoding	Presence	Description
1	`sessionId`	`SessionId`	field	required
2	`requestTimestampNs`	`TimestampNs`	field	required
3	`serverTimestampNs`	`TimestampNs`	field	required
4	`sessionExpiryTimestampNs`	`TimestampNs`	field	required	Expiry of the current authorization. Not a fixed disconnect time: the gateway renews authorization in the background
5	`keepaliveIntervalMs`	`uint32`	field	required

sessionExpiryTimestampNs is not a fixed disconnect time. The gateway renews the session’s authorization in the background, so you do not need to reconnect when this timestamp passes. Every message is preceded by the standard SBE messageHeader (blockLength, templateId, schemaId, version). See encodings.