diff --git a/lib/notifications.dart b/lib/notifications.dart
index 5e435537b2..e961b57d17 100644
--- a/lib/notifications.dart
+++ b/lib/notifications.dart
@@ -78,34 +78,34 @@ class NotificationService {
     // need to save the value.
     token.value = value;
   }
-}
 
-void _onForegroundMessage(FirebaseRemoteMessage message) {
-  assert(debugLog("notif message: ${message.data}"));
-  _onRemoteMessage(message);
-}
+  static void _onForegroundMessage(FirebaseRemoteMessage message) {
+    assert(debugLog("notif message: ${message.data}"));
+    _onRemoteMessage(message);
+  }
 
-Future<void> _onBackgroundMessage(FirebaseRemoteMessage message) async {
-  // This callback will run in a separate isolate from the rest of the app.
-  // See docs:
-  //   https://firebase.flutter.dev/docs/messaging/usage/#background-messages
-  assert(() {
-    debugLogEnabled = true;
-    return true;
-  }());
-  LiveZulipBinding.ensureInitialized();
-  NotificationDisplayManager._init();
-
-  assert(debugLog("notif message in background: ${message.data}"));
-  _onRemoteMessage(message);
-}
+  static Future<void> _onBackgroundMessage(FirebaseRemoteMessage message) async {
+    // This callback will run in a separate isolate from the rest of the app.
+    // See docs:
+    //   https://firebase.flutter.dev/docs/messaging/usage/#background-messages
+    assert(() {
+      debugLogEnabled = true;
+      return true;
+    }());
+    LiveZulipBinding.ensureInitialized();
+    NotificationDisplayManager._init();
+
+    assert(debugLog("notif message in background: ${message.data}"));
+    _onRemoteMessage(message);
+  }
 
-void _onRemoteMessage(FirebaseRemoteMessage message) {
-  final data = FcmMessage.fromJson(message.data);
-  switch (data) {
-    case MessageFcmMessage(): NotificationDisplayManager._onMessageFcmMessage(data, message.data);
-    case RemoveFcmMessage(): break; // TODO handle
-    case UnexpectedFcmMessage(): break; // TODO(log)
+  static void _onRemoteMessage(FirebaseRemoteMessage message) {
+    final data = FcmMessage.fromJson(message.data);
+    switch (data) {
+      case MessageFcmMessage(): NotificationDisplayManager._onMessageFcmMessage(data, message.data);
+      case RemoveFcmMessage(): break; // TODO handle
+      case UnexpectedFcmMessage(): break; // TODO(log)
+    }
   }
 }