WalkBack is a mobile safety app for college students walking alone or in groups at night. It calculates the safest walking route to your destination using well-lit corridors and high-traffic paths, then guides you with live GPS tracking.

Solo Walk — Get a safety-optimized route to your destination with a one-tap SOS button that alerts your emergency contact with your current location.

Buddy System — Match with nearby students heading in the same direction and walk together. Everyone in the group has access to the shared map and SOS feature.

• Frontend: React Native, Expo SDK 54, Expo Router, NativeWind (TailwindCSS)
• Maps: react-native-maps with Google Maps provider, dark map styling, live GPS tracking
• Backend: FastAPI (Python) deployed on Render — POST /api/safest-route
• Routing: GraphHopper with safety-aware path scoring
• Storage: AsyncStorage (on-device, no account required)

• Node.js v20+
• Expo Go app on your phone
• A .env.local file in the SafeMap/ directory with the following keys:

EXPO_PUBLIC_BACKEND_URL=
EXPO_PUBLIC_GH_API_KEY=
EXPO_PUBLIC_SUPABASE_URL=
EXPO_PUBLIC_SUPABASE_ANON_KEY=
EXPO_PUBLIC_MAPBOX_TOKEN=

npm install
npx expo start --tunnel

Scan the QR code with Expo Go on your phone.

SafeMap/
├── app/                  # Screens (file-based routing via Expo Router)
│   ├── (navigation)/     # Home, search, route map
│   ├── (walking)/        # Solo walk, walk completed
│   ├── (buddy)/          # Buddy matching, group walk
│   ├── (settings)/       # Settings, emergency contact
│   └── (onboarding)/     # Profile setup
├── components/           # Shared UI components (MapView, RouteCard, etc.)
├── hooks/                # useLocation
├── lib/                  # routeService, routeStore, profileService
└── constants/            # Colors, theme

The backend repository handles safety-aware route calculation using GraphHopper and is deployed separately on Render. On first request after inactivity, the server may take up to 60 seconds to wake up — the app retries automatically.