3v4l.org

run code in 300+ PHP versions simultaneously
<?php for ($i = 0, $a = array(); $i < 511; $i++) $a = array($a); echo 511, json_encode($a), "\n"; for ($i = 0, $a = array(); $i < 512; $i++) $a = array($a); echo 512, json_encode($a), "\n";

preferences:
37.45 ms | 402 KiB | 5 Q