Brazilian CNPJ (Cadastro Nacional da Pessoa Jurídica) Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching brazilian cnpj (cadastro nacional da pessoa jurídica), 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

# Brazilian CNPJ (Cadastro Nacional da Pessoa Jurídica)
# ReDoS-safe | RegexVault — Identity & PII > National Identity Numbers

import re

brazilian_cnpj_cadastro_nacional_da_pessoa_jurdica_pattern = re.compile(r'^(\d{2})\.?(\d{3})\.?(\d{3})/?([0-9]{4})-?(\d{2})$')

def validate_brazilian_cnpj_cadastro_nacional_da_pessoa_jurdica(value: str) -> bool:
    return bool(brazilian_cnpj_cadastro_nacional_da_pessoa_jurdica_pattern.fullmatch(value))

# Example
print(validate_brazilian_cnpj_cadastro_nacional_da_pessoa_jurdica("11.222.333/0001-81"))  # 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

CNPJ format: 14 digits (8-digit base + 4-digit branch + 2 check digits). Branch 0001 is the main establishment; branches 0002+ are subsidiaries. All-same-digit numbers are invalid. Check digits use weighted sums similar to CPF but different weights.