CardStartDate (FIX tag 503)

LocalMktDateFIX 4.4

CardStartDate (tag 503) is a LocalMktDate field defined in FIX 4.4. It appears in 1 message type, always optionally.

At a glance

Tag: 503
Name: CardStartDate
Datatype: LocalMktDate (String)
Format: YYYYMMDD
Dialects: FIX 4.4
Messages: 1

What the specification says

The start date of the card as specified on the card being used for payment.

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

A real message using tag 503

SettlementInstructions · FIX 4.4

Tag	Field	Wire value	Meaning
8	BeginString	FIX.4.4
9	BodyLength	162
35	MsgType	T	Settlement Instructions
49	SenderCompID	BOARTEAM
56	TargetCompID	COUNTERPARTY
34	MsgSeqNum	2
52	SendingTime	20240101-12:00:00.000
777	SettlInstMsgID	EXAMPLE
160	SettlInstMode	1	Standing Instructions Provided
60	TransactTime	20240101-12:00:00.000
778	NoSettlInst2 entries	2	repeating group
162	SettlInstID	EXAMPLE
503	CardStartDate	20240101
162	SettlInstID	EXAMPLE
503	CardStartDate	20240101
10	CheckSum	067

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 503 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
SettlementInstructions	T	Optional	inside the SettlInstGrp component

Wire format

A calendar date in the market's local timezone, with no time component and no offset. @boarteam/fix keeps the value as a string; format rules are checked by validate(), which reports validate/invalid-value rather than throwing.

Read tag 503 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 field = message.fields[503];field?.name;   // "CardStartDate"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a string

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