FIX Component Definitions

Standard Header & Trailer

The Bullish platform expects standard FIX message header and trailer components on each FIX message sent and received.

Table 1: Standard Header component

Tag	Field Name	Req'd	Type	Comments
8	BeginString	Y	String	FIX.4.4
9	BodyLength	Y	int	Standard FIX message body length
35	MsgType	Y	String	The message type. See relevant section.
49	SenderCompID	Y	String	Agreed CompID of the party sending the message.
56	TargetCompID	Y	String	Agreed CompID of the intended message recipient. BULLISH_PROD for production use. BULLISH_SIMNEXT for testing.
34	MsgSeqNum	Y	int	FIX Message sequence number
50	SenderSubId	C	String	Required when sent from Client into Bullish (non-session layer message only). The identity of the entering trader or system.
57	TargetSubId	N	String	Echoed from the Bullish system to the Client (where present), or ADMIN for administrative messages not intended for a specific user.
43	PossDupFlag	N	Boolean	Whether the message was previously transmitted under the same MsgSeqNum (34). Absence of this field is interpreted as Original Transmission (N).
97	PossResend	N	Boolean	Whether the message was previously transmitted under a different MsgSeqNum (34). Absence of this field is interpreted as Original Transmission (N).
52	SendingTime	Y	UTCTimestamp	Sending time in UTC
122	OrigSendingTime	N	UTCTimestamp	Original message transmission time in UTC where PossDupFlag (43) = Y. If the original time is not available, this should be the same value as SendingTime (52).

Table 2: Standard Trailer component

Tag	Field Name	Req'd	Type	Comments
10	Checksum	Y	String	Standard FIX checksum