Sometimes you may wish to store items in the session only for the next request. You may do so using the flash method. Data stored in the session using this method will only be available during the subsequent HTTP request, and then will be deleted. Flash data is primarily useful for short-lived status messages:
$request->session()->flash('status', 'Task was successful!');
If you need to keep your flash data around for even more requests, you may use the reflash method, which will keep all of the flash data around for an additional request. If you only need to keep specific flash data around, you may use the keep method:
$request->session()->reflash(); $request->session()->keep(['username', 'email']);
Recursos
https://laracasts.com/lessons/flexible-flash-messages
Vegeu Bootstrap els alerts que porta de sèrie
Vegeu SweetAlert
http://t4t5.github.io/sweetalert/