diff --git a/keyserver/src/push/utils.js b/keyserver/src/push/utils.js
--- a/keyserver/src/push/utils.js
+++ b/keyserver/src/push/utils.js
@@ -20,9 +20,11 @@
   'messaging/registration-token-not-registered',
   'messaging/invalid-registration-token',
 ]);
+const fcmMaxMessagePayloadByteSize = 4000;
 const apnTokenInvalidationErrorCode = 410;
 const apnBadRequestErrorCode = 400;
 const apnBadTokenErrorString = 'BadDeviceToken';
+const apnMaxMessagePayloadByteSize = 4096;
 
 type APNPushResult =
   | { +success: true }
@@ -151,6 +153,7 @@
   options: Object,
 ) {
   try {
+    validateAndroidNotificationByteSize(notification);
     const deliveryResult = await provider
       .messaging()
       .sendToDevice(deviceToken, notification, options);
@@ -196,4 +199,24 @@
   return usersToUnreadCounts;
 }
 
-export { apnPush, fcmPush, getUnreadCounts };
+function validateAndroidNotificationByteSize(notification: Object) {
+  const notificationByteSizeExceeded =
+    Buffer.byteLength(JSON.stringify(notification)) >
+    fcmMaxMessagePayloadByteSize;
+  if (
+    notificationByteSizeExceeded &&
+    'custom_notification' in notification.data
+  ) {
+    delete notification.data.custom_notification.messageInfos;
+  } else if (notificationByteSizeExceeded) {
+    delete notification.data.messageInfos;
+  }
+}
+
+export {
+  apnPush,
+  fcmPush,
+  getUnreadCounts,
+  apnMaxMessagePayloadByteSize,
+  fcmMaxMessagePayloadByteSize,
+};