Using our spatie/laravel-short-schedule package you can schedule commands at sub-minute intervals.

// in app\Console\Kernel.php

protected function shortSchedule(\Spatie\ShortSchedule\ShortSchedule $shortSchedule)
{
    // this command will run every second
    $shortSchedule->command('artisan-command')->everySecond();
    
    // this command will run every 30 seconds
    $shortSchedule->command('another-artisan-command')->everySeconds(30);
    
    // this command will run every half a second
    $shortSchedule->command('another-artisan-command')->everySeconds(0.5);
}

In this video, I show you how you can use the package.

I've also recorded another video that shows how the package works under the hood (spoiler: we'll use ReactPHP).