🔔 FCM Push Notification System

A complete end-to-end Firebase Cloud Messaging (FCM) push notification system with Python Flask backend and Android client.

🎯 Features

• Python Backend with Flask and Firebase Admin SDK
• Android App with FCM integration and modern UI
• Real-time Push Notifications from server to device
• RESTful API for notification management
• Device Token Management with registration system
• Sample Notification Content for demonstration

🏗️ Architecture

┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐
│   Android App   │◄──►│  Python Backend  │◄──►│ Firebase Cloud  │
│                 │    │   (Flask API)    │    │   Messaging     │
│ • FCM Token     │    │ • Admin SDK      │    │                 │
│ • Notifications │    │ • Device Tokens  │    │ • Push Service  │
│ • UI Interface  │    │ • Sample Data    │    │ • Delivery      │
└─────────────────┘    └──────────────────┘    └─────────────────┘

📱 Demo Flow

1. Generate FCM Token - Android app creates unique device identifier
2. Register Device - App sends token to backend server
3. Send Notification - Server uses Firebase Admin SDK to push notification
4. Receive & Display - Android app shows notification to user

🚀 Quick Start

Prerequisites

• Python 3.7+
• Android Studio
• Firebase Project with Admin SDK key
• Android device/emulator

Backend Setup

1. Clone the repository:

   git clone https://github.com/Varnika-k/fcm-push-notification-system.git
   cd fcm-push-notification-system

2. Install Python dependencies:

   pip install -r requirements_simple.txt

3. Configure Firebase:

   • Get Firebase Admin SDK key from Firebase Console
   • Update .env file with path to your key:

     FIREBASE_SERVICE_ACCOUNT_KEY=path/to/your/firebase-key.json
     

4. Start the server:

   python app_simple.py

   Server runs on http://localhost:5000

Android Setup

1. Get Firebase configuration:

   • In Firebase Console, add Android app with package com.example.fcmdemo
   • Download google-services.json
   • Place in android_app/app/google-services.json

2. Open in Android Studio:

   • Open android_app folder
   • Let Gradle sync complete
   • Build and run on device/emulator

3. Test the flow:

   • Click "Get FCM Token"
   • Click "Register with Server"
   • Click "Send Test Notification"
   • Check notification tray! 🎉

📚 API Documentation

Endpoints

Method	Endpoint	Description
GET	/	Server status and available endpoints
GET	/notifications	Fetch sample notification content
GET	/devices	List registered devices
POST	/register-device	Register FCM token
POST	/send-notification	Send push notification

Register Device

curl -X POST http://localhost:5000/register-device \
  -H "Content-Type: application/json" \
  -d '{
    "fcm_token": "device_fcm_token_here",
    "device_id": "android_demo_device"
  }'

Send Notification

curl -X POST http://localhost:5000/send-notification \
  -H "Content-Type: application/json" \
  -d '{
    "notification_id": 1,
    "title": "Custom Title",
    "body": "Custom message"
  }'

🗂️ Project Structure

fcm-push-notification-system/
├── README.md                           # This file
├── app_simple.py                       # Flask backend server
├── requirements_simple.txt             # Python dependencies
├── .env                               # Environment configuration
├── test_system.py                     # System testing script
├── .gitignore                         # Git ignore rules
├── START_HERE.md                      # Quick start guide
├── ANDROID_SETUP_GUIDE.md            # Android setup instructions
├── SETUP_INSTRUCTIONS.md             # Detailed setup guide
└── android_app/                      # Complete Android project
    ├── app/
    │   ├── build.gradle               # Android dependencies
    │   ├── google-services.json.template  # Firebase config template
    │   └── src/main/
    │       ├── AndroidManifest.xml
    │       ├── java/com/example/fcmdemo/
    │       │   ├── MainActivity.java      # Main app activity
    │       │   └── FCMService.java        # FCM service handler
    │       └── res/                       # Android resources
    ├── build.gradle                   # Project-level Gradle
    └── settings.gradle               # Gradle settings

🔧 Configuration

Backend Configuration (.env)

# Firebase Configuration
FIREBASE_SERVICE_ACCOUNT_KEY=path/to/firebase-key.json

# Server Configuration  
FLASK_PORT=5000
FLASK_DEBUG=True

Android Configuration

• Package Name: com.example.fcmdemo
• Firebase Config: google-services.json in app/ folder
• Server URL: Configure in MainActivity.java
  • Emulator: http://10.0.2.2:5000
  • Real device: http://YOUR_IP:5000

📱 Android App Features

• Modern Material Design UI with CardView components
• FCM Token Generation with error handling
• Server Registration with HTTP client
• Push Notification Reception with custom service
• Permission Handling for Android 13+ notifications
• Real-time Status Updates with user feedback

🖥️ Backend Features

• Flask REST API with CORS support
• Firebase Admin SDK Integration for FCM
• In-memory Token Storage (easily extendable to database)
• Sample Notification Content for demonstration
• Error Handling with detailed logging
• Development Server with hot reload

🔐 Security Features

• Firebase Keys Protected - Never committed to repository
• Environment Variables for sensitive configuration
• Input Validation on API endpoints
• Error Handling without exposing internals

🧪 Testing

Test Backend:

python test_system.py

Test API Endpoints:

# Server status
curl http://localhost:5000/

# Sample notifications
curl http://localhost:5000/notifications

# Registered devices
curl http://localhost:5000/devices

🚨 Troubleshooting

Problem	Solution
Firebase not initialized	Check firebase key path in .env
Android app crashes	Ensure google-services.json exists
No notifications received	Check device notification permissions
Server connection failed	Update server URL in Android app

📈 Future Enhancements

• Database Integration (PostgreSQL/MongoDB)
• User Authentication and authorization
• Notification History and analytics
• Scheduled Notifications with cron jobs
• Notification Templates and personalization
• Web Dashboard for notification management
• Multiple Device Support per user
• Push Notification Analytics and metrics

🤝 Contributing

1. Fork the repository
2. Create feature branch (git checkout -b feature/amazing-feature)
3. Commit changes (git commit -m 'Add amazing feature')
4. Push to branch (git push origin feature/amazing-feature)
5. Open Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

• Firebase for Cloud Messaging service
• Flask for Python web framework
• Android Firebase SDK team
• Material Design for UI components

📞 Support

For support and questions:

• Open an Issue
• Check Documentation
• Review Setup Guides

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🚀 Ready to send your first push notification? Follow START_HERE.md