developers:fixapi:logon

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LOGON [35=A]

The Logon message initiates a FIX session with authentication and session configuration.

Required credentials:

Tag Field Description
49 SenderCompID T4 Application Name
56 TargetCompID T4 Firm Name
553 UserName T4 User
554 Password T4 Password
91 SecureData License Code (use 112A04B0-5AAF-42F4-994E-FA7CB959C60B for T4Example)
90 SecureDataLen Length of license code
Value Function
d Disable AutoPortfolio refresh
BB Disable auto account subscription
c Enable security definitions
8 Enable pending execution reports
D, RD, CD Enable decimal pricing D=Raw Decimal, RD=Real Decimal, CD=Clearing Decimal
BA Drop copy mode (reporting only)
BG Dynamic account notifications
CB Disable user notifications
V Chart data requests
UCG Multi-Trader mode
V Enable exchange symbols

Message Direction: Client → T4

Tag Field Name Type Req'd Description
Message Header Y MsgType = A
91 SecureData String Y Application license code
90 SecureDataLen Int Y License code length
98 EncryptMethod Int Y Always 0 (none)
108 HeartBtInt Int Y Heartbeat interval (30 seconds)
553 UserName String Y T4 User
554 Password String Y T4 Password
925 NewPassword String O Change password
1408 DefaultCstmApplVerID String O API version
1407 DefaultApplExtID String O Application fingerprint
384 NoMsgTypes Int O Number of RefMsgTypes
→372 RefMsgType String C Session properties (see table)
Message Trailer Y

Logon Request:

8=FIX.4.2|9=200|35=A|49=T4Example|56=T4|52=20130607-14:47:22.872|
91=112A04B0-5AAF-42F4-994E-FA7CB959C60B|90=36|98=0|108=30|
553=username|554=password|384=2|372=d|372=D|10=123|

Logon Response:

8=FIX.4.2|9=150|35=A|49=T4|56=T4Example|50=T4FIX|52=20130607-14:47:24.085|
98=0|108=30|553=username|554=***|1408=4.1.1.1|10=234|
  • Session must start with sequence number 1
  • Dropped connections require new session (sequence 1)
  • Default behavior: AutoPortfolio refresh and account subscription enabled
  • User must have assigned accounts and exchanges before API usage
  • Failed authentication returns Logout with error description
  • developers/fixapi/logon.1780775967.txt.gz
  • Last modified: 2026/06/06 19:59
  • by rob