diff --git a/backend/app/api/auth/__init__.py b/backend/app/api/auth/__init__.py
index f3f74eb..1e5b0ba 100644
--- a/backend/app/api/auth/__init__.py
+++ b/backend/app/api/auth/__init__.py
@@ -1,4 +1,5 @@
 import os
+import json
 import shutil
 from uuid import uuid4
 from typing import Annotated, Optional
@@ -12,11 +13,26 @@ from app.schemas.user import PassengerCreate, Token, UserResponse, LoginRequest,
 import firebase_admin
 from firebase_admin import auth as firebase_auth, credentials
 
-# Initialize Firebase Admin
+# Initialize Firebase Admin SDK
+# Supports two methods:
+#   1. FIREBASE_SERVICE_ACCOUNT_JSON env var with the full JSON as a string (recommended for Render/production)
+#   2. GOOGLE_APPLICATION_CREDENTIALS env var pointing to a JSON file path (local dev)
 try:
     if not firebase_admin._apps:
-        # Default initialization (uses GOOGLE_APPLICATION_CREDENTIALS)
-        firebase_admin.initialize_app()
+        sa_json = os.environ.get("FIREBASE_SERVICE_ACCOUNT_JSON")
+        if sa_json:
+            # Parse the JSON string directly from environment variable
+            sa_dict = json.loads(sa_json)
+            cred = credentials.Certificate(sa_dict)
+            firebase_admin.initialize_app(cred)
+            print("DEBUG: Firebase Admin initialized from FIREBASE_SERVICE_ACCOUNT_JSON env var")
+        elif os.environ.get("GOOGLE_APPLICATION_CREDENTIALS"):
+            # Use file path from GOOGLE_APPLICATION_CREDENTIALS
+            firebase_admin.initialize_app()
+            print("DEBUG: Firebase Admin initialized from GOOGLE_APPLICATION_CREDENTIALS file")
+        else:
+            print("WARNING: No Firebase credentials found. Set FIREBASE_SERVICE_ACCOUNT_JSON or GOOGLE_APPLICATION_CREDENTIALS.")
+            firebase_admin.initialize_app()
 except Exception as e:
     print(f"WARNING: Firebase Admin could not be initialized: {e}")
 
diff --git a/frontend/src/firebaseConfig.ts b/frontend/src/firebaseConfig.ts
index cfc85ac..6d48c7e 100644
--- a/frontend/src/firebaseConfig.ts
+++ b/frontend/src/firebaseConfig.ts
@@ -1,5 +1,11 @@
 import { initializeApp } from 'firebase/app';
-import { getAuth, GoogleAuthProvider, signInWithPopup } from 'firebase/auth';
+import {
+    getAuth,
+    GoogleAuthProvider,
+    signInWithPopup,
+    signInWithRedirect,
+    getRedirectResult
+} from 'firebase/auth';
 
 const firebaseConfig = {
     apiKey: "AIzaSyAG8nmGLHYmXGkl018NjW2sMcIiutM4ne0",
@@ -14,17 +20,46 @@ const app = initializeApp(firebaseConfig);
 export const auth = getAuth(app);
 export const googleProvider = new GoogleAuthProvider();
 
-export const signInWithGoogle = async () => {
-    try {
+// Detect if the user is on a mobile device
+const isMobile = () => {
+    return /Android|iPhone|iPad|iPod|Opera Mini|IEMobile|WPDesktop/i.test(navigator.userAgent);
+};
+
+/**
+ * Signs in with Google.
+ * - Uses signInWithPopup on desktop (fast, no page reload)
+ * - Uses signInWithRedirect on mobile (avoids popup blocking on mobile browsers)
+ */
+export const signInWithGoogle = async (): Promise<{ user: any; token: string }> => {
+    if (isMobile()) {
+        // On mobile, redirect flow is more reliable
+        await signInWithRedirect(auth, googleProvider);
+        // The page will reload; the result is handled by getGoogleRedirectResult() on app load
+        // We return a never-resolving promise to keep the UI in loading state
+        return new Promise(() => { });
+    } else {
+        // On desktop, use popup
         const result = await signInWithPopup(auth, googleProvider);
-        // This gives you a Google Access Token. You can use it to access the Google API.
         const token = await result.user.getIdToken();
-        return {
-            user: result.user,
-            token: token
-        };
-    } catch (error) {
-        console.error("Error signing in with Google", error);
-        throw error;
+        return { user: result.user, token };
+    }
+};
+
+/**
+ * Call this once when the app loads (e.g., in App.vue or main.ts) to
+ * handle the result from a Google redirect login on mobile.
+ * Returns null if there is no pending redirect result.
+ */
+export const getGoogleRedirectResult = async (): Promise<{ user: any; token: string } | null> => {
+    try {
+        const result = await getRedirectResult(auth);
+        if (result && result.user) {
+            const token = await result.user.getIdToken();
+            return { user: result.user, token };
+        }
+        return null;
+    } catch (error) {
+        console.error("Error getting redirect result:", error);
+        return null;
     }
 };
diff --git a/frontend/src/views/AuthView.vue b/frontend/src/views/AuthView.vue
index a97ce8c..54d0de0 100644
--- a/frontend/src/views/AuthView.vue
+++ b/frontend/src/views/AuthView.vue
@@ -1,10 +1,36 @@
 <script setup lang="ts">
-import { ref } from 'vue'
+import { ref, onMounted } from 'vue'
+import { useRouter } from 'vue-router'
 import LoginForm from '@/components/auth/LoginForm.vue'
 import RegisterForm from '@/components/auth/RegisterForm.vue'
+import { getGoogleRedirectResult } from '@/firebaseConfig'
+import { authService } from '@/services/authService'
+import { useAuthStore } from '@/stores/auth'
 
 const isLogin = ref(true)
 const toggleAuth = () => { isLogin.value = !isLogin.value }
+const router = useRouter()
+const authStore = useAuthStore()
+
+// Handle redirect result from Google Sign-In on mobile
+// (signInWithRedirect reloads the page; we catch the result here on load)
+onMounted(async () => {
+  try {
+    const result = await getGoogleRedirectResult()
+    if (result) {
+      const response = await authService.googleLogin(result.token)
+      authStore.login(response.access_token, response.role, response.full_name)
+      const role = response.role.toUpperCase()
+      if (role === 'ADMIN') router.push('/admin')
+      else if (role === 'DRIVER') router.push('/driver')
+      else if (role === 'PROMOTER') router.push('/promoter')
+      else router.push('/map')
+    }
+  } catch (e) {
+    // No redirect result pending, or error — ignore silently
+    console.warn('Google redirect result:', e)
+  }
+})
 </script>
 
 <template>
diff --git a/render.yaml b/render.yaml
index 79306dd..d9314e9 100644
--- a/render.yaml
+++ b/render.yaml
@@ -18,6 +18,10 @@ services:
         value: "false"
       - key: PYTHON_VERSION
         value: 3.13.0
+      # Firebase Admin SDK credentials (JSON string of service account)
+      # Set this manually in the Render dashboard — do NOT commit the actual value
+      - key: FIREBASE_SERVICE_ACCOUNT_JSON
+        sync: false
 
 databases:
   - name: sibu-db