The Logon <A> message authenticates a user and starts a session. It must be the first message sent by any application requesting to initiate a FIX session. A message of the same type will be sent to acknowledge the logon.

Tag	Field Name	Data Type	Req’d	Comments
Standard header			Y	MsgType `35=A`
98	EncryptMethod	int	Y	Method of encryption. Valid values: `0` - None / other
108	HeartBtInt	int	Y	Heartbeat interval (seconds).
141	ResetSeqNumFlag	boolean	N	Indicates that both sides of the FIX session should reset sequence numbers. Valid Values: `Y` - Yes, reset sequence numbers `N` - No (default)
553	Username	string	Y	UserId (provided during onboarding)
554	Password	string	Y	Password (provided during onboarding)
Standard trailer			Y