FIX Protocol Tag 108: HeartBtInt
Heartbeat interval in seconds, agreed in the Logon. Each side sends a Heartbeat when it has sent no other message during the interval.
- Tag number
- 108
- Data type
- INT
- FIX versions
- FIX 4.0 to 5.0 SP2 and FIXT 1.1
- Used in
- 1 message type
Practical notes on HeartBtInt
HeartBtInt is the heartbeat interval in seconds, sent on the Logon. Both sides use the same value for the life of the session.
- Each side sends a Heartbeat when it has sent nothing else for this many seconds.
- After a little more than one interval of silence the other side sends a TestRequest; if that goes unanswered too, it drops the connection.
- 30 seconds is the most common value. It must match what the counterparty has configured; some acceptors refuse a Logon with a different value.
Common mistakes
- Very short intervals on busy hosts, where a long pause in the application can trigger a disconnect.
Tag 108 in each FIX version
Values and message usage as defined in a specific version.
Data type
INT: A whole number without a decimal point. It may be negative.
Example
108=30
Illustrative value. In a message, fields are separated by the SOH character (0x01), often shown as | or ^ in logs.
Decode a message with this tagMessage types that use tag 108
- Logon 35=A
Covers every version from FIX 4.0 to 5.0 SP2, including fields reached through components and repeating groups. The version pages above show whether the tag is required in each message.
Field and message data comes from the QuickFIX data dictionaries for FIX 4.0 to 5.0 SP2 and FIXT 1.1, used under the QuickFIX Software License. This product includes software developed by quickfixengine.org (http://www.quickfixengine.org/). Enumerated value names are converted to plain text for reading.