Korean Postal Code (5-digit, post-2015) Regex for Python

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching korean postal code (5-digit, post-2015), 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

# Korean Postal Code (5-digit, post-2015)
# ReDoS-safe | RegexVault — Localization > Postal Codes

import re

korean_postal_code_5digit_post2015_pattern = re.compile(r'^[0-9]{5}$')

def validate_korean_postal_code_5digit_post2015(value: str) -> bool:
    return bool(korean_postal_code_5digit_post2015_pattern.fullmatch(value))

# Example
print(validate_korean_postal_code_5digit_post2015("03000"))  # 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

South Korea switched from the old 6-digit format (XXX-XXX) to a new 5-digit system in August 2015. The old format is no longer valid for new addresses. North Korea is not covered by this system.