ApplNewSeqNum (FIX tag 1399)

SeqNumFIX 5.0 SP2

ApplNewSeqNum (tag 1399) is a SeqNum field defined in FIX 5.0 SP2. It appears in 1 message type, always optionally.

At a glance

Tag
1399
Name
ApplNewSeqNum
Datatype
SeqNum (int)
Dialects
FIX 5.0 SP2
Messages
1

What the specification says

Used to specify a new application sequence number.

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

A real message using tag 1399

ApplicationMessageReport · FIX 5.0 SP2
TagFieldWire valueMeaning
8BeginStringFIXT.1.1
9BodyLength131
35MsgTypeBYApplicationMessageReport
49SenderCompIDBOARTEAM
56TargetCompIDCOUNTERPARTY
34MsgSeqNum2
52SendingTime20240101-12:00:00.000
1356ApplReportIDEXAMPLE
1426ApplReportType0Reset ApplSeqNum to new value specified in ApplNewSeqNum(1399)
1351NoApplIDs2 entries2repeating group
1355RefApplIDEXAMPLE
1399ApplNewSeqNum1
1355RefApplIDEXAMPLE
1399ApplNewSeqNum1
10CheckSum219
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 5.0 SP2 dictionary and verified at build time: it parses and validates with no issues. Open the decoder to try your own message.

Where tag 1399 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.

MessageMsgTypeRequirednessWhere in the message
ApplicationMessageReportBYOptionalinside the ApplIDReportGrp component

Wire format

A positive sequence number. Session-level, and monotonic within a session. @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 1399 in TypeScript

decode.tsts
import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix50sp2";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);const field = message.fields[1399];field?.name;   // "ApplNewSeqNum"field?.raw;    // the verbatim wire stringfield?.value;  // coerced to a number

Other SeqNum 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-fix50sp2