Indonesian KTP (Kartu Tanda Penduduk) NIK Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching indonesian ktp (kartu tanda penduduk) nik, 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

# Indonesian KTP (Kartu Tanda Penduduk) NIK
# ReDoS-safe | RegexVault — Identity & PII > National Identity Numbers

import re

indonesian_ktp_kartu_tanda_penduduk_nik_pattern = re.compile(r'^[1-9][0-9]{1}[0-9]{2}[0-9]{2}((?:(?:[04][1-9]|[1256][0-9]|[37][01])|(?:[04][1-9]|[1256][0-9]|[37][01])))(0[1-9]|1[0-2])(\d{2})(\d{4})$')

def validate_indonesian_ktp_kartu_tanda_penduduk_nik(value: str) -> bool:
    return bool(indonesian_ktp_kartu_tanda_penduduk_nik_pattern.fullmatch(value))

# Example
print(validate_indonesian_ktp_kartu_tanda_penduduk_nik("3171011504890001"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > National Identity Numbers 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

NIK structure: 2-digit province code (11-99) + 2-digit city/regency + 2-digit district + 2-digit day/gender (women have +40 to day) + 2-digit month + 2-digit year + 4-digit sequence. Female DOB: day+40 encodes gender.