Vero OMS Docs

Session messages control authentication, liveness, sequence recovery, and orderly disconnect. All session messages use the standard FIX header and trailer.

Session message list

Message	`MsgType (35)`	Direction	Purpose
Logon	`A`	Client to service; service to client	Opens a FIX session and negotiates heartbeat and sequence behavior.
Heartbeat	`0`	Both directions	Confirms that the FIX connection is alive.
TestRequest	`1`	Both directions	Requests an immediate heartbeat response when a peer appears idle.
ResendRequest	`2`	Both directions	Requests retransmission for a missing sequence range.
Reject	`3`	Service to client	Rejects a session-level message or invalid session condition.
SequenceReset	`4`	Both directions	Advances sequence state or fills gaps for messages that are not resent.
Logout	`5`	Both directions	Closes the FIX session or reports a session condition that requires disconnect.

Logon fields

Logon (35=A) opens a session.

Tag	Name	Req	Type	Description
`98`	`EncryptMethod`	Y	Int	Encryption method. Use `0` for none unless a different value is assigned for the session.
`108`	`HeartBtInt`	Y	Int	Heartbeat interval in seconds. Must be greater than `15` and less than `100`.
`141`	`ResetSeqNumFlag`	N	Boolean	`Y` resets sequence numbers for the session. `N` continues the previous sequence state.

Heartbeat fields

Heartbeat (35=0) contains no required body fields in this contract. When replying to TestRequest (35=1), include the received TestReqID (112).

Test request fields

Tag	Name	Req	Type	Description
`112`	`TestReqID`	Y	String	Identifier that the peer echoes in the heartbeat response.

Resend request fields

Tag	Name	Req	Type	Description
`7`	`BeginSeqNo`	Y	Int	First sequence number requested.
`16`	`EndSeqNo`	Y	Int	Last sequence number requested. Use `0` to request all messages from `BeginSeqNo (7)` onward.

Reject fields

Tag	Name	Req	Type	Description
`45`	`RefSeqNum`	Y	Int	Sequence number of the rejected message.
`58`	`Text`	N	String	Human-readable reject detail.
`371`	`RefTagID`	N	Int	FIX tag that caused the reject, when applicable.
`372`	`RefMsgType`	Y	String	`MsgType (35)` of the rejected message.
`373`	`SessionRejectReason`	N	Int	FIX session reject reason code.

Sequence reset fields

Tag	Name	Req	Type	Description
`36`	`NewSeqNo`	Y	Int	Next sequence number expected after the reset or gap fill.
`123`	`GapFillFlag`	N	Boolean	`Y` indicates a gap fill. Omitted or `N` indicates a sequence reset.

Logout fields

Tag	Name	Req	Type	Description
`58`	`Text`	N	String	Logout detail. If the value states `MsgSeqNum too low, expecting X but received Y`, relogon with `MsgSeqNum (34)=X`.

Overview

Integrations

Authentication

REST API

Streaming API

FIX API

Session messages

Session message list

Logon fields

Heartbeat fields

Test request fields

Resend request fields

Reject fields

Sequence reset fields

Logout fields

​Session message list

​Logon fields

​Heartbeat fields

​Test request fields

​Resend request fields

​Reject fields

​Sequence reset fields

​Logout fields

Session message list

Logon fields

Heartbeat fields

Test request fields

Resend request fields

Reject fields

Sequence reset fields

Logout fields