3v4l.org

run code in 300+ PHP versions simultaneously
<?php $m = md5('abcdefghijklmnopqrstuvwxyz012345password'); echo $m."\n"; for ($i=0;$i<10;$i++) { $m = md5($m); echo $m."\n"; }

preferences:
39.32 ms | 402 KiB | 5 Q