Using a Custom Validator

By default, ramsey/uuid validates UUID strings with the lenient validator Ramsey\Uuid\Validator\GenericValidator. This validator ensures the string is 36 characters, has the dashes in the correct places, and uses only hexadecimal values. It does not ensure the string is of the RFC 4122 variant or contains a valid version.

The validator Ramsey\Uuid\Rfc4122\Validator validates UUID strings to ensure they match the RFC 4122 variant and contain a valid version. Since it is not enabled by default, you will need to configure ramsey/uuid to use it, if you want stricter validation.

Set an alternate validator to use for Uuid::isValid()
use Ramsey\Uuid\Rfc4122\Validator as Rfc4122Validator;
use Ramsey\Uuid\Uuid;
use Ramsey\Uuid\UuidFactory;

$factory = new UuidFactory();
$factory->setValidator(new Rfc4122Validator());


if (!Uuid::isValid('2bfb5006-087b-9553-5082-e8f39337ad29')) {
    echo "This UUID is not valid!\n";


If you want to use your own validation, create a class that implements Ramsey\Uuid\Validator\ValidatorInterface and use the same method to set your validator on the factory.