HandlInst (FIX tag 21)

charFIX 4.4FIX 4.2

HandlInst (tag 21) is a char field defined in FIX 4.4 and FIX 4.2. It appears in 8 message types, always optionally. It is an enumerated field with 3 defined values.

At a glance

Tag
21
Name
HandlInst
Datatype
char
Dialects
FIX 4.4 and FIX 4.2
Messages
8
Valid values
3

What the specification says

Instructions for order handling on Broker trading floor

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

A real message using tag 21

NewOrderSingle · FIX 4.4
TagFieldWire valueMeaning
8BeginStringFIX.4.4
9BodyLength116
35MsgTypeDOrder – Single
49SenderCompIDBOARTEAM
56TargetCompIDCOUNTERPARTY
34MsgSeqNum2
52SendingTime20240101-12:00:00.000
11ClOrdIDORD-10042
21HandlInst1Automated execution order, private, no Broker intervention
54Side1Buy
60TransactTime20240101-12:00:00.000
40OrdType1Market
10CheckSum199
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
1Automated execution order, private, no Broker interventionAUTOMATED_EXECUTION_ORDER_PRIVATE_NO_BROKER_INTERVENTION / AutomatedExecutionNoIntervention
2Automated execution order, public, Broker intervention OKAUTOMATED_EXECUTION_ORDER_PUBLIC_BROKER_INTERVENTION_OK / AutomatedExecutionInterventionOK
3Manual order, best executionMANUAL_ORDER_BEST_EXECUTION / ManualOrder

Where tag 21 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.

MessageMsgTypeFIX 4.4FIX 4.2Where in the message
CrossOrderCancelReplaceRequesttOptionaldirectly on the message body
ExecutionReport8OptionalOptionaldirectly on the message body
MultilegOrderCancelReplaceACOptionaldirectly on the message body
NewOrderCrosssOptionaldirectly on the message body
NewOrderListEOptionalOptionalinside the ListOrdGrp component
NewOrderMultilegABOptionaldirectly on the message body
NewOrderSingleDOptionalRequireddirectly on the message body
OrderCancelReplaceRequestGOptionalRequireddirectly on the message body

Wire format

A single character. Most char fields are enumerated, so the value is one of a fixed set rather than arbitrary text. @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 21 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 handlInst = message.fields[21]?.raw;// e.g. "1" — Automated execution order, private, no Broker intervention// The dictionary also carries the labels:const label = fix.dictionary  .fieldByTag(21)  ?.enumValues?.find((e) => e.value === handlInst)  ?.description;

Other char 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