3v4l.org

run code in 300+ PHP versions simultaneously
<?php echo substr(str_shuffle("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"), 0, 1).substr(md5(time()),1);

preferences:
23.99 ms | 402 KiB | 5 Q