FIXSIM
FIX Protocol Glossary
This glossary defines common terminology used in the Financial Information eXchange (FIX) protocol and electronic trading system testing.
A
Acceptor
The FIX session endpoint that passively waits for incoming connections.
Application Message
A FIX message containing business meaning, such as orders or executions.
C
Cancel Reject
A message indicating an order cancel request could not be processed.
ClOrdID
A unique identifier assigned by the client for an order.
Counterparty
The trading system on the opposite side of a FIX session.
D
Drop Copy
A secondary stream of execution reports used for back-office reconciliation and monitoring.
E
Execution Report
A FIX message describing the status of an order including fills, partial fills, or rejects.
Exchange Simulator
A testing system that emulates exchange behavior for certification or QA testing.
F
Financial Information eXchange (FIX)
A standardized protocol used for electronic communication of trade information.
FIX Engine
Software that manages FIX session connectivity and message encoding/decoding.
FIX Session
A persistent communication channel between two FIX counterparties.
FIX Simulator
A system that emulates a broker or exchange for testing FIX client behavior.
G
Gap Fill
A recovery message used to synchronize message sequence numbers.
H
Heartbeat
A session-level message used to confirm connectivity is still active.
L
Logon
The initial message used to establish a FIX session.
Logout
A message used to terminate a FIX session.
N
New Order Single
A message used to submit a new order to a counterparty.
O
Order Lifecycle
The sequence of states an order passes through from submission to completion.
R
Resend Request
A message requesting retransmission of missed messages.
S
Sequence Number
A counter used to maintain message ordering within a FIX session.
Session Layer
The part of the FIX protocol responsible for connectivity management.
T
Trade Capture Report
A message reporting completed trade details.
Trading Counterparty
The broker or exchange connected via FIX.
U
UAT (User Acceptance Testing)
Pre-production testing performed before a trading system goes live.
Some organizations use commercial FIX simulation platforms such as FIXSIM or internal testing tools to validate the concepts described above.
