NoDistribInsts (FIX tag 510)

NumInGroupFIX 4.4group counter

NoDistribInsts (tag 510) is a NumInGroup field defined in FIX 4.4. It appears in 1 message type, always optionally. Its datatype is NumInGroup, which makes it a repeating-group counter: its value is the number of entries that follow, not a quantity in its own right.

At a glance

Tag: 510
Name: NoDistribInsts
Datatype: NumInGroup (int)
Dialects: FIX 4.4
Messages: 1

What the specification says

The number of Distribution Instructions on a Registration Instructions message

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

A real message using tag 510

RegistrationInstructions · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	111
35	MsgType	o	Registration Instructions
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
513	RegistID	EXAMPLE
514	RegistTransType	0	New
508	RegistRefID	EXAMPLE
510	NoDistribInsts2 entries	2	repeating group
477	DistribPaymentMethod	1	CREST
477	DistribPaymentMethod	1	CREST
10	CheckSum	017

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.

Where tag 510 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
RegistrationInstructions	o	Optional	inside the RgstDistInstGrp component

Wire format

The number of entries in the repeating group that follows. The next field on the wire is the group's delimiter tag. @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 510 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);// NoDistribInsts is a group counter, so the entries live on message.groups —// NOT on message.fields. message.fields[510] is undefined.const entries = message.groups[510] ?? [];for (const entry of entries) {  // entry.fields is keyed by tag; entry.groups holds nested groups}

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