SwiftMt103Parser

SwiftMt103Parser is an educational Spring Boot service that extracts a practical subset of MT103 fields into JSON. It is a portfolio project, not a complete ISO 15022 implementation and not suitable for payment processing without a SWIFT-compliant validation and integration layer.

Supported subset

The parser accepts either plain MT103 text tags or a message containing a {4: ... -} text block.

Tag	JSON field	Requirement
:20:	senderReference	Required, 1-16 basic characters on one line
:23B:	bankOperationCode	Optional
:32A:	valueDate, currency, amount	Required
:50K:, :50A:, :50F:	orderingCustomer	Optional
:59: or :59A:	beneficiaryCustomer	One is required
:70:	remittanceInfo	Optional
:71A:	detailsOfCharges	Optional
:52A:	orderingInstitution	Optional
:57A:	accountWithInstitution	Optional
:72:	senderToReceiverInformation	Optional

Validation matrix

This is a deliberately small, documented validation set. It is not the ISO 15022 field specification.

Field	Length and basic charset checks
:20:	1-16 characters, one line, letters, digits, spaces, and /?:().,'+-{} only
:23B:	Exactly four uppercase letters
:32A:	YYMMDDCCCAMOUNT, where the date is valid, the amount has 1-15 whole digits and an optional comma fraction
:50K:, :50A:, :50F:, :59:, :59A:, :70:, :72:	Up to four lines, each at most 35 characters, using letters, digits, spaces, and /?:().,'+-{}
:71A:	BEN, OUR, or SHA
:52A:, :57A:	Up to two lines, each at most 35 basic characters; the final line must be an uppercase BIC8 or BIC11

Every parsed tag may occur once only. A repeated tag is rejected instead of silently replacing the earlier value.

For :32A:, the supported currency allowlist is AED, AUD, BRL, CAD, CHF, CNY, CZK, DKK, EUR, GBP, HKD, HUF, INR, JPY, MXN, NOK, NZD, PLN, QAR, RON, SAR, SEK, SGD, TRY, USD, and ZAR. JPY must have no fractional amount; the other listed currencies allow up to two fractional digits. The amount is returned as a JSON number using a decimal point.

Limits

• This is an educational subset of MT103, not full ISO 15022 validation.
• It validates only the BIC8/BIC11 shape in :52A: and :57A:. It does not validate BIC registration, account formats, conditional field rules, or network headers.
• It does not connect to SWIFTNet, store messages, support other MT types, or convert messages to ISO 20022/MX.
• Requests cap message at 35,000 characters. API responses include basic browser-facing security headers.

Run

./mvnw test
./mvnw spring-boot:run

On Windows, use mvnw.cmd.

API

Method	Path	Purpose
POST	/api/swift/mt103/parse	Parse one MT103 message
GET	/api/swift/mt103/health	Return SwiftMt103Parser health

curl -X POST http://localhost:8083/api/swift/mt103/parse \
  -H "Content-Type: application/json" \
  -d '{"message":":20:REF123\n:23B:CRED\n:32A:260720EUR12345,67\n:59:BENEFICIARY LTD"}'

Validation failures return HTTP 400 and identify the missing or malformed tag. Fixture messages under src/test/resources/mt103 form the parser regression corpus.

Documentation

• Architecture
• UML
• Static documentation index

License

MIT, see LICENSE.