Australian Postcode Regex for Python

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching australian postcode, ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. 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

# Australian Postcode
# ReDoS-safe | RegexVault — Localization > Postal Codes

import re

australian_postcode_pattern = re.compile(r'^([0-9]{4})$')

def validate_australian_postcode(value: str) -> bool:
    return bool(australian_postcode_pattern.fullmatch(value))

# Example
print(validate_australian_postcode("2000"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Postal Codes 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

Australian postcode ranges by state: NSW/ACT 2000-2999, VIC 3000-3999, QLD 4000-4999, SA 5000-5999, WA 6000-6999, TAS 7000-7999, NT 0800-0999. Leading zeros (NT/ACT) require string storage.