Bank Account Number (Generic Sensitive) Regex for Python

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching bank account number (generic sensitive), ported and verified for Python. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. 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

# Bank Account Number (Generic Sensitive)
# ReDoS-safe | RegexVault — Identity & PII > Financial PII

import re

bank_account_number_generic_sensitive_pattern = re.compile(r'^[0-9]{6,18}$')

def validate_bank_account_number_generic_sensitive(value: str) -> bool:
    return bool(bank_account_number_generic_sensitive_pattern.fullmatch(value))

# Example
print(validate_bank_account_number_generic_sensitive("123456"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Financial PII 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

Bank account numbers vary widely by country: UK 8 digits, US 5-17 digits, Singapore 9-12 digits, India 11-16 digits. This pattern covers the practical range. Always combine with routing/sort code for unambiguous bank identification.