3v4l.org

run code in 300+ PHP versions simultaneously
<?php ob_start(); echo "foo"; ob_start(); echo "bar"; ob_end_clean(); ob_end_flush();
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.5 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
foo

preferences:
189.85 ms | 403 KiB | 160 Q