Prime FIX 5.0 Session Management

In the tables below, the Req column indicates whether a field is required: Y = Required, N = Optional, C = Conditional on another field or product.

All messages on this page include the standard header and trailer fields.

Session management messages

Logon (A)

Initiates a FIX session connection between your client and the server.

Tag	Name	Data Type	Req	Description
95	RawDataLength	Int	Y	Number of bytes in the RawData field
96	RawData	text	Y	Signature
98	EncryptMethod	Int	Y	`0` = None
108	HeartBtInt	Int	Y	Heartbeat interval in seconds (recommended: 30)
141	ResetSeqNumFlag	Boolean	N	`Y` = Reset sequence numbers to 1
553	Username	String	Y	Client username for authentication
554	Password	String	Y	Client password for authentication
1137	DefaultApplVerID	String	Y	`9` = FIX 5.0 Service Pack 2
9406	DropCopyFlag	Char	N	`N` = Execution reports for orders from this session only; `Y` = Execution reports for all portfolio orders and fills (default). Market data sessions must use `N`.

Logout (5)

Terminates a FIX session gracefully.

Tag	Name	Data Type	Req	Description
58	Text	String	N	Logout reason or informational message

Heartbeat (0)

Maintains session connectivity and confirms system responsiveness.

Tag	Name	Data Type	Req	Description
112	TestReqID	String	C	Required if responding to TestRequest. Echo the TestReqID from the TestRequest message.

TestRequest (1)

Validates session responsiveness when no messages are received within the HeartBtInt period.

Tag	Name	Data Type	Req	Description
112	TestReqID	String	Y	Unique identifier that must be echoed in Heartbeat response

Reject (3)

Indicates session-level rejection of a received message.

Tag	Name	Data Type	Req	Description
45	RefSeqNum	Int	Y	MsgSeqNum of rejected message
371	RefTagID	Int	C	Tag number of the field with error
372	RefMsgType	String	C	MsgType of rejected message
373	SessionRejectReason	Int	C	`0` = Invalid tag number `1` = Required tag missing `2` = Tag not defined `3` = Undefined tag `5` = Value incorrect `6` = Incorrect data format `99` = Other
58	Text	String	N	Human-readable description of rejection

ResendRequest (2)

Requests retransmission of messages when a gap is detected in sequence numbers.

Tag	Name	Data Type	Req	Description
7	BeginSeqNo	Int	Y	Starting sequence number for resend range
16	EndSeqNo	Int	Y	Ending sequence number (`0` = resend all messages after BeginSeqNo)

SequenceReset (4)

Resets message sequence numbers or fills sequence gaps.

Tag	Name	Data Type	Req	Description
123	GapFillFlag	Boolean	C	`Y` = Gap fill mode (messages 34 through NewSeqNo-1 have been skipped)
36	NewSeqNo	Int	Y	New sequence number for next message

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FIX 4.2 API

FIX 5.0 API

Session management messages

Logon (A)

Logout (5)

Heartbeat (0)

TestRequest (1)

Reject (3)

ResendRequest (2)

SequenceReset (4)

​Session management messages

​Logon (A)

​Logout (5)

​Heartbeat (0)

​TestRequest (1)

​Reject (3)

​ResendRequest (2)

​SequenceReset (4)

Session management messages

Logon (A)

Logout (5)

Heartbeat (0)

TestRequest (1)

Reject (3)

ResendRequest (2)

SequenceReset (4)