All FIX messages must begin with header fields and end with a trailer field.
| Tag | Field Name | Data Type | Req’d | Comments |
|---|
| 8 | BeginString | string | Y | Identifies beginning of new message and protocol version. Always the first field in a message. Value is FIX.4.4. |
| 9 | BodyLength | int | Y | Message length, in bytes, forward to the CheckSum <10> field. Always second field in message and unencrypted. |
| 35 | MsgType | string | Y | Defines message type. Always third field in message. |
| 49 | SenderCompID | int | Y | Used to identify a firm which sends the message. |
| 56 | TargetCompID | string | Y | Used to identify a receiving firm. |
| 34 | MsgSeqNum | int | Y | Integer message sequence number. |
| 43 | PosDupFlag | boolean | C | Required for retransmitted messages as a result of ResendRequest. |
| 97 | PossResend | boolean | C | Required when message may be a duplicate of another message sent under a different sequence number. |
| 122 | OrigSendingTime | timestamp | C | Required for messages sent as a result of ResendRequest. Time of original transmission in UTC. |
| 52 | SendingTime | timestamp | Y | Time of message transmission in UTC. |
| Tag | Field Name | Data Type | Req’d | Comments |
|---|
| 10 | CheckSum | int | Y | Simple checksum. Always defined as three characters in the last field in the message. |
