3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php function myCallback($buffer, $flags) { if ($flags & PHP_OUTPUT_HANDLER_START) { header('Server: LastMinuteHeaderServer'); } } ob_start('myCallback'); echo "Hello World!"; ob_end_flush();
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0