MessageEncoding (FIX tag 347)

StringFIX 4.4FIX 4.2session envelope

MessageEncoding (tag 347) is a String field defined in FIX 4.4 and FIX 4.2. It belongs to the session envelope: every FIX 4.4 message carries it, so it identifies the session rather than describing the business event. It is an enumerated field with 4 defined values.

At a glance

Tag
347
Name
MessageEncoding
Datatype
String
Dialects
FIX 4.4 and FIX 4.2
Messages
93
Valid values
4

What the specification says

Type of message encoding (non-ASCII (non-English) characters) used in a message’s "Encoded" fields.

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

A real message using tag 347

NewOrderSingle · FIX 4.4
TagFieldWire valueMeaning
8BeginStringFIX.4.4
9BodyLength127
35MsgTypeDOrder – Single
49SenderCompIDBOARTEAM
56TargetCompIDCOUNTERPARTY
34MsgSeqNum2
52SendingTime20240101-12:00:00.000
347MessageEncodingISO-2022-JPJIS
11ClOrdIDORD-10042
54Side1Buy
60TransactTime20240101-12:00:00.000
40OrdType1Market
10CheckSum120
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.

ValueMeaningSymbolic name
ISO-2022-JPJISJIS / ISO2022JP
EUC-JPEUCEUC / EUCJP
Shift_JISfor using SJISFOR_USING_SJIS / ShiftJIS
UTF-8UnicodeUNICODE / UTF8

Where tag 347 appears

Session envelope field
Tag 347 appears in every one of the 93 FIX 4.4 message types, because it is part of the standard header or trailer. Listing them all would say nothing useful — it is present on anything you will ever decode.

Wire format

Free-form text. Any byte except the SOH separator is legal, so values are not trimmed or case-folded on the wire. @boarteam/fix keeps the value as a string; format rules are checked by validate(), which reports validate/invalid-value rather than throwing.

Read tag 347 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 messageEncoding = message.fields[347]?.raw;// e.g. "ISO-2022-JP" — JIS// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(347)  ?.enumValues?.find((e) => e.value === messageEncoding)  ?.description;

Other String fields

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