diff --git a/002_source/ionic_mobile/src/ERRORS.ts b/002_source/ionic_mobile/src/ERRORS.ts
new file mode 100644
index 0000000..33f8d33
--- /dev/null
+++ b/002_source/ionic_mobile/src/ERRORS.ts
@@ -0,0 +1 @@
+export const ERR_POCKETBASE_URL_IS_EMPTY = 'POCKETBASE url is empty';
diff --git a/002_source/ionic_mobile/src/constants.tsx b/002_source/ionic_mobile/src/constants.tsx
index 80a9d44..3698f36 100644
--- a/002_source/ionic_mobile/src/constants.tsx
+++ b/002_source/ionic_mobile/src/constants.tsx
@@ -8,6 +8,10 @@
 // 0.0.7 - add back button for listening practice, matching frenzy, connective revision
 // 0.0.8 - add back button for listening practice card, matching frenzy card, connective revision card
 // 0.0.9 - fix ticket 26,27,28,29
+import { Capacitor } from '@capacitor/core';
+
+import { ERR_POCKETBASE_URL_IS_EMPTY } from './ERRORS';
+
 // 0.0.10 - remove debug symbol and re-route ending page
 const VERSIONS = 'v0.0.10';
 const HELLOWORLD_MP3 = '/helloworld.mp3';
@@ -76,11 +80,14 @@ const TEST = process.env.NODE_ENV === 'test';
 const MY_FAVORITE = 'My Favorite';
 
 //
+if (!import.meta.env.VITE_POCKETBASE_URL) throw new Error(ERR_POCKETBASE_URL_IS_EMPTY);
 const POCKETBASE_URL = import.meta.env.VITE_POCKETBASE_URL;
 //
 // database constants
 export const COL_USERS = 'users';
 export const COL_USER_METAS = 'UserMetas';
+//
+export const RUNNING_PLATFORM = Capacitor.getPlatform();
 
 export {
   //