Some sample configuration.

config/app.php

@@ -115,6 +115,7 @@ return [
          */
         'Illuminate\Foundation\Providers\ArtisanServiceProvider',
         'Illuminate\Auth\AuthServiceProvider',
+        'Illuminate\Broadcasting\BroadcastServiceProvider',
         'Illuminate\Bus\BusServiceProvider',
         'Illuminate\Cache\CacheServiceProvider',
         'Illuminate\Foundation\Providers\ConsoleSupportServiceProvider',

config/broadcast.php

+<?php
+
+return [
+
+    /*
+    |--------------------------------------------------------------------------
+    | Default Broadcaster
+    |--------------------------------------------------------------------------
+    |
+    | This option controls the default broadcaster that will be used by the
+    | framework when an event needs to be broadcast. You may set this to
+    | any of the connections defined in the "connections" array below.
+    |
+    */
+
+    'default' => env('BROADCAST_DRIVER', 'pusher'),
+
+    /*
+    |--------------------------------------------------------------------------
+    | Broadcast Connections
+    |--------------------------------------------------------------------------
+    |
+    | Here you may define all of the broadcast connections that will be used
+    | to broadcast events to other systems or over websockets. Samples of
+    | each available type of connection are provided inside this array.
+    |
+    */
+
+    'connections' => [
+
+        'pusher' => [
+            'driver' => 'pusher',
+            'key'    => env('PUSHER_KEY'),
+            'secret' => env('PUSHER_SECRET'),
+            'app_id' => env('PUSHER_APP_ID'),
+        ],
+
+    ],
+
+];