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  | Required  | Comments  | 
|---|---|---|---|
Standard Header  | Yes  | MsgType <35> = A  | |
98  | EncryptMethod  | Yes  | Method of encryption  | 
108  | HeartBtInt  | Yes  | Heartbeat interval in seconds.  | 
141  | ResetSeqNumFlag  | No  | Indicates that the both sides of the FIX session should reset sequence numbers  | 
553  | Username  | Yes  | User Id (provided during onboarding)  | 
554  | Password  | Yes  | Password (provided during onboarding)  | 
1137  | DefaultApplVerID  | Yes*  | The default version of FIX message used in this session: 
  | 
Standard trailer  | Yes  |