sound

The sound to play when a recipient receives a push notification that's based on the message template. You can use the default stream or specify the file name of a sound resource that's bundled in your app. On an Android platform, the sound file must reside in /res/raw/.

For an iOS platform, this value is the key for the name of a sound file in your app's main bundle or the Library/Sounds folder in your app's data container. If the sound file can't be found or you specify default for the value, the system plays the default alert sound.