Header & Trailer

Every FIX message must include a standard header and trailer. The header contains essential routing and sequence information, while the trailer provides message integrity verification.

FIX Specification

MESSAGE BODY

8 - BeginString string required

FIX.4.4. Must be the first field in the message.

9 - BodyLength integer required

Must be the second field in the message.

35 - MsgType string required

Must be the third field in the message.

49 - SenderCompID string required

Provided by Customer during onboarding.

56 - TargetCompID string required

Provided by Customer during onboarding.

34 - MsgSeqNum integer required

Message sequence number.

43 - PossDupFlag boolean

Always required for retransmitted messages, whether prompted by the sending system or as the result of a resend request.

97 - PossResend boolean

Required when the message may be duplicate of another message sent under a different sequence number.

52 - SendingTime string required

Format: YYYYMMDD-HH:MM:SS.uuu

Time of message transmission expressed in UTC.

122 - OrigSendingTime string

Format: YYYYMMDD-HH:MM:SS.uuu

Required for message re-sent as a result of a ResendRequest. If data is not available set to same value as SendingTime (52).

10 - CheckSum string required

Three byte, simple checksum. See the FIX spec for details.