title: Playing custom notification sound using Cloud Functions - iOS
body: <p>I'm sending notification to my client app using <code>Cloud Functions</code> and <code>GoogleCloudMessaging</code> in this way:</p>
  <pre><code>const notificationContent = {
            notification: {
              title: `${senderName} has sent you a message`,
              body: `${messageString}`,
              icon: &quot;default&quot;,
              sound: &quot;customNotificationSound&quot;,
            },
          };
          return admin.messaging()
              .sendToDevice(notifToken, notificationContent)
              .then((result) =&gt;{
                console.log(&quot;write done correctly&quot;);
              });
  </code></pre>
  <p>I want to use a custom notification sound instead of the default one; so I followed some guides online like <a href="https://firebase.google.com/docs/cloud-messaging/http-server-ref#notification-payload-support" rel="nofollow noreferrer">this</a>, <a href="https://developer.apple.com/library/archive/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/SupportingNotificationsinYourApp.html#//apple_ref/doc/uid/TP40008194-CH4-SW1" rel="nofollow noreferrer">this</a> and <a href="https://medium.com/@prakash.maharjan/play-custom-push-notification-sound-ios-a767748a46" rel="nofollow noreferrer">this</a> but they don't seem to answer my question.</p>
  <p>Since I'm sending the push notification from the cloud function, do I still need to load the sound file in the client Main Bundle (I tried it and in fact it doesn't seem to work).</p>
  <p>Or do I have to upload it somewhere else?</p>
  <p>P.s. also the sound file extension is .wav so there shouldn't be problems for that matter.</p>