ResetSeqNumFlag (FIX tag 141)

BooleanFIX 4.4FIX 4.2FIX 5.0 SP2

ResetSeqNumFlag (tag 141) is a Boolean field defined in FIX 4.4, FIX 4.2 and FIX 5.0 SP2. It appears in 1 message type, always optionally. It is an enumerated field with 2 defined values.

At a glance

Tag: 141
Name: ResetSeqNumFlag
Datatype: Boolean (char)
Dialects: FIX 4.4, FIX 4.2 and FIX 5.0 SP2
Messages: 1
Valid values: 2

What the specification says

FIX 4.4

Indicates that the both sides of the FIX session should reset sequence numbers.

FIX 4.2

Indicates that the both sides of the FIX session should reset sequence numbers.

FIX 5.0 SP2

Indicates that both sides of the FIX session should reset sequence numbers.

Descriptions are quoted from the FIX Orchestra sources under the Apache 2.0 licence.

A real message using tag 141

Logon · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	80
35	MsgType	A	Logon
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
98	EncryptMethod	0	None / other
108	HeartBtInt	1
141	ResetSeqNumFlag	N	No
10	CheckSum	199

Edit and decode it yourself

Shown with | separators for readability. On the wire FIX uses SOH (0x01), an invisible control byte — and because BodyLength and CheckSum are computed over the actual bytes, the two forms have different checksums. Both are valid and both decode here.

Open in the full decoder →

Generated from the FIX 4.4 dictionary and verified at build time: it parses and validates with no issues. Open the decoder to try your own message.

Valid values

A value outside this list is not a parse error — the message still decodes — but validate() reports it as validate/value-not-in-enum.

Value	Meaning	Symbolic name
Y	Yes, reset sequence numbers	YES / Yes / YES_RESET_SEQUENCE_NUMBERS
N	No	NO / No

Where tag 141 appears

Requiredness is a property of the message, not of the field: the same tag can be optional in one message and conditionally required in another.

Message	MsgType	FIX 4.4	FIX 4.2	FIX 5.0 SP2	Where in the message
Logon	A	Optional	Optional	Optional	directly on the message body

Wire format

Y or N. Not 1/0, and not true/false. @boarteam/fix keeps the value as a string and, for enumerated fields, reports validate/value-not-in-enum when it is not a defined value.

Read tag 141 in TypeScript

decode.tsts

import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix44";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);const resetSeqNumFlag = message.fields[141]?.raw;// e.g. "Y" — Yes, reset sequence numbers// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(141)  ?.enumValues?.find((e) => e.value === resetSeqNumFlag)  ?.description;

Decode this in your own code

The same engine that produced the decoded example above is an Apache-2.0 npm package with zero runtime dependencies. It runs in Node and in the browser, and parse() returns problems as data instead of throwing.

npm i @boarteam/fix @boarteam/fix-dict-fix44

Try the decoder Source on GitHub