-- Planned Frontend: Expo/React Native (in development)
+- Frontend: Expo/React Native (implemented with Google/Firebase authentication)

+import os
+from pathlib import Path
+
 # Path to your Firebase Admin SDK JSON
-cred = credentials.Certificate("../firebase_service_account.json")
-firebase_admin.initialize_app(cred)
+def initialize_firebase():
+    """Initialize Firebase Admin SDK with proper error handling."""
+    try:
+        # Use environment variable or fallback to relative path
+        credentials_path = os.getenv(
+            'FIREBASE_CREDENTIALS_PATH', 
+            '../firebase_service_account.json'
+        )
+        
+        if not Path(credentials_path).exists():
+            raise FileNotFoundError(f"Firebase credentials file not found: {credentials_path}")
+        
+        cred = credentials.Certificate(credentials_path)
+        firebase_admin.initialize_app(cred)
+        print("Firebase Admin SDK initialized successfully")
+    except Exception as e:
+        print(f"Failed to initialize Firebase Admin SDK: {e}")
+        raise
+
+# Initialize Firebase
+initialize_firebase()

-const API_URL = "Your API URL here"; // Replace with your actual API URL
+const API_URL = process.env.EXPO_PUBLIC_API_URL || "http://10.0.2.2:8000";

 const [request, response, promptAsync] = Google.useAuthRequest({
-  webClientId: "your-web-client-id.apps.googleusercontent.com",
-  androidClientId: "your-android-client-id.apps.googleusercontent.com",
+  webClientId: process.env.EXPO_PUBLIC_GOOGLE_WEB_CLIENT_ID,
+  androidClientId: process.env.EXPO_PUBLIC_GOOGLE_ANDROID_CLIENT_ID,
 });

 } catch (err: any) {
   console.log("Google Sign-In Error:", err);
-  alert("Login failed. Check network connection.");
+  const errorMessage = err.response?.data?.detail || 
+                      err.message || 
+                      "Google sign-in failed. Please try again.";
+  alert(errorMessage);
 }

 useEffect(() => {
   axios.defaults.baseURL = API_URL;
-  axios.interceptors.request.use((config) => {
+  const requestInterceptor = axios.interceptors.request.use((config) => {
     if (accessToken) config.headers.Authorization = `Bearer ${accessToken}`;
     return config;
   });

-  axios.interceptors.response.use(
+  const responseInterceptor = axios.interceptors.response.use(
     (res) => res,
     async (error) => {
       // ... existing code ...
     }
   );

   const loadTokens = async () => {
     // ... existing code ...
   };
   loadTokens();
+
+  return () => {
+    axios.interceptors.request.eject(requestInterceptor);
+    axios.interceptors.response.eject(responseInterceptor);
+  };
 }, []);

--- a/frontend/contexts/AuthContext.tsx
+++ b/frontend/contexts/AuthContext.tsx
 useEffect(() => {
   axios.defaults.baseURL = API_URL;

-  axios.interceptors.request.use((config) => {
-    if (accessToken) config.headers.Authorization = `Bearer ${accessToken}`;
-    return config;
-  });
-
-  axios.interceptors.response.use(
-    (res) => res,
-    async (error) => { /* refresh logic */ }
-  );
+  const reqInterceptor = axios.interceptors.request.use((config) => {
+    if (accessToken) config.headers.Authorization = `Bearer ${accessToken}`;
+    return config;
+  });
+
+  const resInterceptor = axios.interceptors.response.use(
+    (res) => res,
+    async (error) => {
+      // existing 401/refresh logic
+    }
+  );
+
+  return () => {
+    axios.interceptors.request.eject(reqInterceptor);
+    axios.interceptors.response.eject(resInterceptor);
+  };
-}, []);
+}, [accessToken, refreshToken]);

 const firebaseConfig = {
-  apiKey: "<YOUR_API_KEY>",
-  authDomain: "<YOUR_AUTH_DOMAIN>",
-  projectId: "<YOUR_PROJECT_ID>",
-  storageBucket: "<YOUR_STORAGE_BUCKET>",
-  messagingSenderId: "<YOUR_MESSAGING_SENDER_ID>",
-  appId: "<YOUR_APP_ID>",
+  apiKey: process.env.EXPO_PUBLIC_FIREBASE_API_KEY,
+  authDomain: process.env.EXPO_PUBLIC_FIREBASE_AUTH_DOMAIN,
+  projectId: process.env.EXPO_PUBLIC_FIREBASE_PROJECT_ID,
+  storageBucket: process.env.EXPO_PUBLIC_FIREBASE_STORAGE_BUCKET,
+  messagingSenderId: process.env.EXPO_PUBLIC_FIREBASE_MESSAGING_SENDER_ID,
+  appId: process.env.EXPO_PUBLIC_FIREBASE_APP_ID,
   // measurementId: "<YOUR_MEASUREMENT_ID>" // Only if you enabled Google Analytics
 };

--- frontend/package.json
@@ lines 25
-   "firebase": "^9.22.2",
+   "firebase": "^12.0.0",

 const redirectUri = AuthSession.makeRedirectUri({});
-console.log("Redirect URI:", redirectUri);
+if (__DEV__) {
+  console.log("Redirect URI:", redirectUri);
+}

-<Image source={{ uri: "https://img.icons8.com/color/48/google-logo.png" }} style={styles.googleIcon} />
+<Image source={require("../assets/google-logo.png")} style={styles.googleIcon} />

[phases.install]
cmds = [
-    "pip install --upgrade pip",
-    "pip install -r requirements.txt"
+    # (Optional) upgrade pip via the Python executable to avoid PATH ambiguity
+    "python -m pip install --upgrade pip",
+    # Install backend requirements first; fall back to root requirements.txt
+    "pip install -r backend/requirements.txt || pip install -r requirements.txt"
]