You controller method should be called getAvailableResponders not searchResponders.

And you probably need to return json_encode($results), not echo them.

How would the controllermethod be called? Could you make up an example please? I changed to return json_encode, but it doesn't change

You specify the method to call in your routes:

Route::post('searchResponders', 'RespondersController@getAvailableResponders');

That getAvailableResponders after @ is the method that will called.

The method is specified in my routes file. But I can't directly call that method, as then the app would search for a wrong URL /getAvailableResponders

http://laravel.io/forum/04-29-2015-people-asking-about-jquery-ajax

You should use return response(); If you could use route() helper on that ajax url, that would be great.