ISO 20022 Message Type Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching iso 20022 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

# ISO 20022 Message Type
# ReDoS-safe | RegexVault — Finance > Financial Formats

import re

iso_20022_message_type_pattern = re.compile(r'^[a-z]{4}\.[0-9]{3}\.[0-9]{3}\.[0-9]{2}$')

def validate_iso_20022_message_type(value: str) -> bool:
    return bool(iso_20022_message_type_pattern.fullmatch(value))

# Example
print(validate_iso_20022_message_type("pacs.008.001.08"))  # 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

ISO 20022 message ID: 4-char business area (pacs=payments clearing, pain=payment initiation, camt=cash management, sese=settlement) + 3-digit message number + 001 (version) + 2-digit variant.