STANDARD TRAILER

The Standard Trailer terminates all FIX messages with a checksum for message integrity.

Required in all messages

• Sum all bytes in message (excluding checksum field)
• Modulo 256 of sum
• Format as three-digit string with leading zeros

8=FIX.4.2|9=73|35=0|49=SENDER|56=TARGET|34=1|52=20120101-12:00:00.000|10=215|
                                                                      ^^^^^^
                                                                     Checksum

• Always unencrypted
• Must be the last field
• Exactly 3 characters (pad with zeros)
• Delimiter (SOH) follows checksum