Open source · MIT

@ohmyfin/swift-draft

A zero-dependency TypeScript library for drafting, validating and translating SWIFT MT (MT103/202/202COV/199) and ISO 20022 MX (pacs.008/009/002, camt.053/054) messages. Works in Node 20+ and modern browsers without polyfills. This page itself is running the library entirely client-side — no network calls.

Install

npm install @ohmyfin/swift-draft

Or drop the UMD bundle into a static page:

<script src="https://unpkg.com/@ohmyfin/swift-draft@latest/dist/swift-draft.umd.min.js"></script>
<script>
  const report = SwiftDraft.validate("MT103", { /* payload */ });
</script>

30-second example

import { serializeMt, validate } from "@ohmyfin/swift-draft";

const payload = {
  senderBic: "DEUTDEFFXXX",
  receiverBic: "NWBKGB2LXXX",
  uetr: "eb6305c9-1f7f-4def-aaee-805b6e8b3b1a",
  fields: {
    "20":  "TXN-2026-0001",
    "23B": "CRED",
    "32A": { valueDate: "260525", currency: "EUR", amount: "1234,56" },
    "50K": "/DE89370400440532013000\nACME GMBH\nBERLIN",
    "59":  "/GB82WEST12345698765432\nBETA LTD\nLONDON",
    "70":  "INVOICE 2026-0001",
    "71A": "SHA",
  },
};

if (!validate("MT103", payload).ok) throw new Error("invalid");
const fin = serializeMt("MT103", payload);

Live demo (runs in your browser, no server)

Sender BIC

Receiver BIC

UETR (RFC 4122 v4 lowercase)

Sender's reference (field 20)

Value date (YYMMDD)

Currency

Amount (comma decimal)

Charges (71A)

Ordering customer (50K) Beneficiary (59) Remittance info (70)

Generated FIN message

What it supports

MT — MT103, MT103 STP, MT202, MT202COV, MT199 (full 5-block FIN serialisation; round-trip parser).
MX (ISO 20022) — pacs.008.001.08, pacs.009.001.08 (core + COV), pacs.002.001.10, camt.053.001.08, camt.054.001.08 (XML with optional BizMsgEnvlp AppHdr).
Primitives — BIC (ISO 9362), IBAN (ISO 13616 mod-97), currency (ISO 4217), country (ISO 3166-1), SWIFT date YYMMDD, ISO 8601, UETR (RFC 4122 v4), MT/MX amount formats, MT 71A charge codes, ISO 20022 charge bearers.
Cross-field rules — CBPR+ STP intermediary ban, 33B currency / amount consistency, COV underlying-sequence presence, etc.