3v4l.org

run code in 300+ PHP versions simultaneously
<?php $bcrypt = '$2a$12$9SIfjYSVOTw8xFn98DadmOYKMSyReSktMvm/tfiLFDYb.oGvO8LEC'; $bcryptNeedsRehash = preg_replace('/\$\d{2}\$/', '$' . 12 . '$', $bcrypt); var_dump($bcrypt, $bcryptNeedsRehash);

preferences:
36.63 ms | 402 KiB | 5 Q