RefApplExtID (FIX tag 1406)

intFIX 5.0 SP2

RefApplExtID (tag 1406) is an int field defined in FIX 5.0 SP2. It appears in 3 message types, always optionally.

At a glance

Tag: 1406
Name: RefApplExtID
Datatype: int
Dialects: FIX 5.0 SP2
Messages: 3

What the specification says

The extension pack number associated with an application message.

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

A real message using tag 1406

Logon · FIX 5.0 SP2

Tag	Field	Wire value	Meaning
8	BeginString	FIXT.1.1
9	BodyLength	125
35	MsgType	A	Logon Message
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
98	EncryptMethod	0	None
108	HeartBtInt	1
384	NoMsgTypes2 entries	2	repeating group
372	RefMsgType	EXAMPLE
1406	RefApplExtID	1
372	RefMsgType	EXAMPLE
1406	RefApplExtID	1
1137	DefaultApplVerID	9
10	CheckSum	181

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 5.0 SP2 dictionary and verified at build time: it parses and validates with no issues. Open the decoder to try your own message.

Where tag 1406 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	Requiredness	Where in the message
BusinessMessageReject	j	Optional	directly on the message body
Logon	A	Optional	inside the MsgTypeGrp component
Reject	3	Optional	directly on the message body

Wire format

A whole number, optionally signed. Leading zeros are legal on the wire and are preserved in the raw value. @boarteam/fix parses the value as a number and reports parse/invalid-int when it does not lex as one; the raw string is kept either way.

Read tag 1406 in TypeScript

decode.tsts

import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix50sp2";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);const field = message.fields[1406];field?.name;   // "RefApplExtID"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a number

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-fix50sp2

Try the decoder Source on GitHub