Payment Reference (End-to-End ID) Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching payment reference (end-to-end id), 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

# Payment Reference (End-to-End ID)
# ReDoS-safe | RegexVault — Finance > Financial Formats

import re

payment_reference_endtoend_id_pattern = re.compile(r'^[A-Za-z0-9\-/\?:\(\)\.,'\+ ]{1,35}$')

def validate_payment_reference_endtoend_id(value: str) -> bool:
    return bool(payment_reference_endtoend_id_pattern.fullmatch(value))

# Example
print(validate_payment_reference_endtoend_id("NOTPROVIDED"))  # 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 allows the SEPA character set in payment references: A-Z, a-z, 0-9, and / - ? : ( ) . , ' + space. The # symbol is excluded. Use NOTPROVIDED if no reference is available (SEPA convention).