Utility function/class to validate CNPJ (Brazilian employer ID).

PHP Support

Passing ✔	Passing ✔	Passing ✔	Passing ✔

Installation

# using Composer
$ composer require lacus/cnpj-val

Import

<?php
// Using class-based resource
use Lacus\CnpjVal\CnpjValidator;

// Or using function-based one
use function Lacus\CnpjVal\cnpj_val;

Usage

Object-Oriented Usage

$validator = new CnpjValidator();
$cnpj = '98765432000198';

echo $validator->isValid($cnpj) ? 'Valid' : 'Invalid';  // returns 'Valid'

$cnpj = '98.765.432/0001-98';
echo $validator->isValid($cnpj) ? 'Valid' : 'Invalid';  // returns 'Valid'

$cnpj = '98765432000199';
echo $validator->isValid($cnpj) ? 'Valid' : 'Invalid';  // returns 'Invalid'

Imperative programming

The helper function cnpj_val() is just a functional abstraction. Internally it creates an instance of CnpjValidator and calls the isValid() method right away.

$cnpj = '98765432000198';

echo cnpj_val($cnpj) ? 'Valid' : 'Invalid';      // returns 'Valid'

echo cnpj_val('98.765.432/0001-98') ? 'Valid' : 'Invalid';  // returns 'Valid'

echo cnpj_val('98765432000199') ? 'Valid' : 'Invalid';      // returns 'Invalid'

Validation Examples

// Valid CNPJ numbers
cnpj_val('98765432000198')      // returns true
cnpj_val('98.765.432/0001-98')  // returns true
cnpj_val('03603568000195')      // returns true

// Invalid CNPJ numbers
cnpj_val('98765432000199')      // returns false
cnpj_val('12345678901234')      // returns false
cnpj_val('00000000000000')      // returns false
cnpj_val('11111111111111')      // returns false
cnpj_val('123')                 // returns false (too short)
cnpj_val('')                    // returns false (empty)

Features

• ✅ Format Agnostic: Accepts CNPJ with or without formatting (dots, slashes, dashes)
• ✅ Strict Validation: Validates both check digits according to Brazilian CNPJ algorithm
• ✅ Type Safety: Built with PHP 8.1+ strict types
• ✅ Lightweight: Minimal dependencies, only requires lacus/cnpj-gen for check digit calculation
• ✅ Dual API: Both object-oriented and functional programming styles supported

API Reference

CnpjValidator Class

isValid(string $cnpjString): bool

Validates a CNPJ string and returns true if valid, false otherwise.

Parameters:

• $cnpjString (string): The CNPJ to validate (with or without formatting)

Returns:

• bool: true if the CNPJ is valid, false otherwise

cnpj_val() Function

cnpj_val(string $cnpjString): bool

Functional wrapper around CnpjValidator::isValid().

Parameters:

• $cnpjString (string): The CNPJ to validate (with or without formatting)

Returns:

• bool: true if the CNPJ is valid, false otherwise

Validation Algorithm

The package validates CNPJ using the official Brazilian algorithm:

1. Length Check: Ensures the CNPJ has exactly 14 digits
2. First Check Digit: Calculates and validates the 13th digit
3. Second Check Digit: Calculates and validates the 14th digit
4. Format Tolerance: Automatically strips non-numeric characters before validation

Error Handling

The validator is designed to be forgiving with input format but strict with validation:

• Invalid formats (too short, too long) return false
• Invalid check digits return false
• Empty strings return false
• Non-numeric strings (after stripping formatting) return false

Dependencies

• PHP: >= 8.1
• lacus/cnpj-gen: ^1.0 (for check digit calculation)

Contribution & Support

We welcome contributions! Please see our Contributing Guidelines for details. But if you find this project helpful, please consider:

• ⭐ Starring the repository
• 🤝 Contributing to the codebase
• 💡 Suggesting new features
• 🐛 Reporting bugs

License

This project is licensed under the MIT License - see the LICENSE file for details.

Changelog

See CHANGELOG for a list of changes and version history.

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Made with ❤️ by Lacus Solutions