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

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 PHP. 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 PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

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

define('BRAZILIAN_CNPJ_CADASTRO_NACIONAL_DA_PESSOA_JURDICA_PATTERN', '/^(\d{2})\.?(\d{3})\.?(\d{3})\/?([0-9]{4})-?(\d{2})$/');

function validate_brazilian_cnpj_cadastro_nacional_da_pessoa_jurdica(string $input): bool {
    return (bool) preg_match(BRAZILIAN_CNPJ_CADASTRO_NACIONAL_DA_PESSOA_JURDICA_PATTERN, $input);
}

// Example
var_dump(validate_brazilian_cnpj_cadastro_nacional_da_pessoa_jurdica("11.222.333/0001-81")); // bool(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 PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. 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.