3v4l.org

run code in 500+ PHP versions simultaneously
<?php foreach (["2021-12-25", "2022-01-01"] as $d) { echo "$d is a ".date_format(date_create($d), "l").PHP_EOL; } ?>
Output for 8.2.0 - 8.2.34, 8.3.0 - 8.3.35, 8.4.1 - 8.4.26, 8.5.0 - 8.5.11
2021-12-25 is a Saturday 2022-01-01 is a Saturday

preferences:
29.46 ms | 1136 KiB | 7 Q