x940

x940 is under active development and may not yet be production-ready. APIs, output formats, and behavior may change between releases as the parser evolves to handle more MT940 dialects, edge cases, and SWIFT variations. Feedback, bug reports, and contributions are welcome.

High-performance MT940 bank statement parser. Converts legacy SWIFT MT940 files to JSON, CSV, and ISO 20022 camt.053 XML.

Built in Rust with native Python, Node.js, WASM, and CLI bindings.

Installation

Python

pip install x940

CLI

cargo install x940

Node.js

npm install x940

WASM

npm install x940-wasm

Rust

[dependencies]
x940rs = "0.1.1"

Build from Source

git clone git@github.com:tahzeer/x940.git
cd x940

# CLI: build and install the binary directly
cargo install --path crates/cli

# Rust library: add to your project via path
# Cargo.toml:  x940rs = { path = "/path/to/x940/crates/core" }

# Python binding: install in dev mode
uv pip install maturin
uv run maturin develop -m crates/python/Cargo.toml --release
uv run pytest crates/python/tests/ -v

# Node.js binding: build the native addon
cd crates/node && npm install && napi build --platform --release

# WASM binding: build with wasm-pack
rustup target add wasm32-unknown-unknown
curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
cd crates/wasm && npm test

# Run tests
cargo test -p x940rs -p x940
uv run pytest crates/python/tests/ -v
cd crates/node && npm test

# Lint
cargo clippy --workspace -- -D warnings
cargo fmt --check

# Bump version across all packages
./bump.sh 0.2.0

# Benchmarks
cargo bench -p x940rs

Quick Start

import x940 as x

stmt = x.MT940(open("statement.sta").read())
stmt.to_json()     # -> JSON string
stmt.to_csv()      # -> CSV string with UTF-8 BOM
stmt.to_camt053()  # -> camt.053.001.06 XML

x940 transform statement.sta --format json --output result.json
x940 transform statement.sta --format csv  --output result.csv
cat statement.sta | x940 transform --format csv > txns.csv

const { MT940 } = require("x940");
const stmt = new MT940(data, "auto");
stmt.toJSON();
stmt.toCSV();
stmt.toCamt053();

// WASM (browser, Deno, Bun, Node.js)
import { MT940 } from "x940-wasm";
const stmt = new MT940(data, "auto");
stmt.toJson();
stmt.toCsv();
stmt.toCamt053();

use x940rs::{parse_mt940, DecoderChain, to_json};

let chain = DecoderChain::auto();
let statements = parse_mt940(&raw, &chain)?;
let json = to_json(&statements)?;

Features

• 4 Tag 86 dialect decoders with per-transaction auto-detection: SWIFT structured (/KEYWORD/VALUE), German GVC (?DD), Polish/Nordic angular (<DD / ^DD), unstructured fallback
• 3 export formats: JSON, CSV (UTF-8 BOM), camt.053.001.06 XML
• SWIFT-compliant: Handles :61: continuation lines, reversals (RD/RC), entry date inference
• Exact decimal math using rust_decimal (no IEEE 754 float drift)
• GIL released during parse for concurrent Python threads
• Multi-statement files: Handles multiple :20: blocks in one file

Resolver Options

Resolver	Description
auto	Auto-detect per-transaction (default)
swift	SWIFT /KEYWORD/VALUE structured format
gvc	German ?DD GVC format
angular	Polish/Nordic <DD / ^DD format

Resolvers are priority hints, not hard locks. Unmatched transactions fall back to the unstructured safety net: no data loss.

Bindings

Binding	Technology
Rust	Native crate
Python	PyO3 + Maturin
CLI	Native binary
Node.js/TS	napi-rs
WASM	wasm-bindgen

License

GPL-3.0-or-later. See LICENSE.

References

• MT940 Format Reference: SWIFT tag specifications, dialect formats, ZKA subfield codes
• Usage Guide: In-depth examples for Python, Node.js, CLI, and Rust
• Technical Architecture: Design decisions, data flow, parser internals