CustomerOrFirm (FIX tag 204)

intFIX 4.2

CustomerOrFirm (tag 204) is an int field defined in FIX 4.2. It appears in 3 message types, always optionally. It is an enumerated field with 2 defined values.

At a glance

Tag: 204
Name: CustomerOrFirm
Datatype: int
Dialects: FIX 4.2
Messages: 3
Valid values: 2

What the specification says

Used for options when delivering the order to an execution system/exchange to specify if the order is for a customer or the firm placing the order itself.

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

A real message using tag 204

OrderSingle · FIX 4.2

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.2
9	BodyLength	133
35	MsgType	D	Order Single
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
11	ClOrdID	ORD-10042
21	HandlInst	1	Automated execution order, private, no Broker intervention
55	Symbol	EUR/USD
54	Side	1	Buy
60	TransactTime	20240101-12:00:00.000
40	OrdType	1	Market
204	CustomerOrFirm	0	Customer
10	CheckSum	119

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 4.2 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
0	Customer	Customer
1	Firm	Firm

Where tag 204 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
OrderCancelReplaceRequest	G	Optional	directly on the message body
OrderList	E	Optional	directly on the message body
OrderSingle	D	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 204 in TypeScript

decode.tsts

import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix42";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);const customerOrFirm = message.fields[204]?.raw;// e.g. "0" — Customer// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(204)  ?.enumValues?.find((e) => e.value === customerOrFirm)  ?.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-fix42

Try the decoder Source on GitHub