Easy to use PHP Bitcoin and Litecoin address validator. One day I will add other crypto currencies. Or how about you? :)
use Merkeleon\PhpCryptocurrencyAddressValidation\Validation;
$validator = Validation::make('BTC');
var_dump($validator->validate('1QLbGuc3WGKKKpLs4pBp9H6jiQ2MgPkXRp'));