diff --git a/lib/utils/__mocks__/config.js b/lib/utils/__mocks__/config.js
--- a/lib/utils/__mocks__/config.js
+++ b/lib/utils/__mocks__/config.js
@@ -56,6 +56,7 @@
     getNotifByteSize: jest.fn(),
     normalizeUint8ArrayForBlobUpload: jest.fn(),
   },
+  showAlert: jest.fn(),
 });
 
 const hasConfig = (): boolean => true;
diff --git a/lib/utils/config.js b/lib/utils/config.js
--- a/lib/utils/config.js
+++ b/lib/utils/config.js
@@ -31,6 +31,7 @@
   +olmAPI: OlmAPI,
   +sqliteAPI: SQLiteAPI,
   +encryptedNotifUtilsAPI: EncryptedNotifUtilsAPI,
+  +showAlert: (title: string, message: string) => mixed,
 };
 
 let registeredConfig: ?Config = null;
diff --git a/native/config.js b/native/config.js
--- a/native/config.js
+++ b/native/config.js
@@ -1,6 +1,6 @@
 // @flow
 
-import { Platform } from 'react-native';
+import { Alert, Platform } from 'react-native';
 
 import { registerConfig } from 'lib/utils/config.js';
 
@@ -24,4 +24,5 @@
   olmAPI,
   sqliteAPI,
   encryptedNotifUtilsAPI,
+  showAlert: Alert.alert,
 });
diff --git a/web/app.react.js b/web/app.react.js
--- a/web/app.react.js
+++ b/web/app.react.js
@@ -128,6 +128,8 @@
   olmAPI,
   sqliteAPI,
   encryptedNotifUtilsAPI,
+  showAlert: (title: string, message: string) =>
+    window.alert(`${title}: ${message}`),
 });
 
 const versionBroadcast = new BroadcastChannel('comm_version');