laravel/app/Providers/BroadcastServiceProvider.php

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\Broadcast;

class BroadcastServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        Broadcast::routes();

        Broadcast::auth('example.*', function ($user, $exampleId) {
            return true;
        });
    }
}