FIX Session
FIX sessions provide deterministic ordering, liveness checks, and gap recovery for institutional integrations.
Logon
Clients establish a session with Logon (35=A). The message includes standard
session fields plus Senticore authentication tags for signed challenge response.
| Field | FIX tag | Notes |
|---|---|---|
| BeginString | 8 | FIX.4.4 or FIXT.1.1 |
| MsgType | 35 | A |
| SenderCompID | 49 | Client-assigned institutional identifier |
| TargetCompID | 56 | Senticore gateway identifier |
| MsgSeqNum | 34 | Starts at 1 unless reset was agreed |
| SendingTime | 52 | UTC timestamp |
| EncryptMethod | 98 | 0 over TLS |
| HeartBtInt | 108 | Negotiated heartbeat interval |
Authentication extension tags are provided during onboarding and are stable per credential.
Heartbeat and liveness
The gateway sends Heartbeat (35=0) according to HeartBtInt. If either side
needs an explicit liveness check, it sends TestRequest (35=1) and expects a
Heartbeat carrying the matching TestReqID.
Sequence recovery
Clients must support:
ResendRequest(35=2) for sequence gapsSequenceReset(35=4) for administrative reset- duplicate detection through
PossDupFlag - idempotent handling of repeated
ExecutionReportmessages
Logout
Sessions terminate with Logout (35=5). Unclean disconnects can trigger
cancel-on-disconnect behavior when enabled for market-maker accounts.