SWIFT Message Type Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching swift message type, ported and verified for Python. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# SWIFT Message Type
# ReDoS-safe | RegexVault — Finance > Financial Formats

import re

swift_message_type_pattern = re.compile(r'^MT(?:0[0-9]{2}|[1-9][0-9]{2})$')

def validate_swift_message_type(value: str) -> bool:
    return bool(swift_message_type_pattern.fullmatch(value))

# Example
print(validate_swift_message_type("MT103"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Financial Formats category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Common SWIFT messages: MT103=customer credit transfer, MT202=bank transfer, MT700=LC issuance, MT940=statement, MT950=confirmation. Category 1=customer payments, 2=bank transfers, 7=documentary, 9=statements.