SMS Mitra — Android Dual-SIM SMS Gateway & Scheduled Dispatch System (Flutter + Node.js)

SMS Mitra is an enterprise-grade, cost-effective Mobile SMS Gateway platform that turns physical Android smartphones into powerful outbound SMS dispatch engines. Eliminate expensive third-party SMS aggregator fees (Twilio, AWS SNS, Msg91) by routing cloud dispatch tasks through your local dual-SIM cellular subscriptions with automated quota management, real-time status reporting, and background resilience.

🌟 Key Features

• ⚡ Physical Dual-SIM Gateway: Detects physical SIM cards, carrier names, and slot IDs with dynamic drag-and-drop priority routing.
   
• ⏰ Precision Scheduled SMS Engine: Schedule single outbound SMS messages for any future date & time with auto-retry and real-time status updates.
   
• 🔁 Recurring & Frequently Sending SMS: Set automated recurring campaigns (Daily, Alternate Days, Weekly, Monthly, or Custom intervals) with instant pause/resume toggles.
   
• ⚡ Dual Dispatch Channels: High-priority Firebase Cloud Messaging (FCM) push wakeups + low-latency WebSockets for instant live status reconciliation.
   
• 📊 Strict Quota & Limit Enforcement: Configure per-SIM daily/monthly dispatch limits (e.g. 100/day or unlimited) with real-time UI warning badges.
   
• 📑 Detailed Reports & PDF Export: Filter dispatch history by date range, SIM carrier, or status, and export clean PDF reports with one tap.
   
• 🛡️ Secure REST API & Code Snippets: Built-in developer sandbox with auto-generated integration code snippets in cURL, Node.js, Python, PHP, and Dart.
   
• 🔋 Background Reliability: Engineered with battery optimization bypass and unhandled async error recovery to run 24/7 without interruption.
   

🛠️ Architecture & Tech Stack

Mobile App (Android Gateway):

• Built with Flutter 3.x & Dart 3.x
• State Management: Riverpod 2.6
• Local Storage & Caching: Hive & Flutter Secure Storage
• Native Telephony: Custom Kotlin MethodChannel with SmsManager

Backend Server:

• Node.js & Express 5.x REST API
• Real-time Engine: Socket.IO (WebSockets)
• Database: MySQL 8.x via Sequelize ORM (Auto-migration schema)
• Push Notifications: Firebase Admin SDK (FCM)
• Background Worker: High-reliability cron scheduler daemon

📦 What You Will Get (ZIP Package)

1. Complete Flutter Gateway App Source Code (sms_app/)
2. Complete Node.js Express REST API Server (server/)
3. Comprehensive Documentation & Setup Guides (README.md, server/README.md, sms_app/README.md)
4. Clean Configuration Templates (.env.example, serviceAccountKey.json.example, firebase_config.dart)
5. Full Automated Test Suite (64+ unit, widget, and DI tests included)

📋 Requirements & Prerequisites

• Server: Node.js 18+ and MySQL 8.x (Local or Cloud Server like cPanel, VPS, AWS, DigitalOcean)
• Mobile: Android Smartphone running Android 8.0 (API 26) or higher with active physical SIM card(s)
• Firebase: Free Firebase Project for Firebase Cloud Messaging (FCM)
• Development (Optional): Flutter 3.24+ for building/modifying the Android APK