🚀 Overview

Duet Pro VPN is a powerful and privacy-focused VPN app source code that provides both free and premium server connections
with subscription-based monetization. Built using Flutter (for Android/iOS) and integrated with popular ad networks such as
AdMob, Facebook Audience Network, and StartApp, this app offers a complete monetized VPN
experience for developers aiming to build a branded and scalable VPN service.

Experience (E): Designed after modern VPN UX patterns—quick connect, smart routing, data usage limits, and transparent subscriptions—ensuring
both user trust and revenue optimization through hybrid monetization models.

✨ Key Features

• ⚡ Fast One-Tap Connection: Instantly connect to the nearest high-speed server.
• 🛡️ Military-Grade Encryption: Protects user data with secure tunneling and DNS leak prevention.
• 🌍 Global VPN Servers: Supports multiple regions—switch between free and premium nodes.
• 💳 Subscription System: Built-in premium model with monthly/annual in-app purchases.
• 💰 Hybrid Monetization: AdMob, Facebook Ads, and StartApp integration (banner, interstitial, and rewarded ads).
• 📊 Usage Analytics: Track session duration, data usage, and connection history.
• 🔔 Push Notifications: Firebase integration for announcements, server maintenance, or upgrades.
• 🌗 Modern UI/UX: Dark/Light themes, clean dashboard, and localized text.
• 🧱 Kill Switch (optional): Prevents leaks during unexpected disconnections.
• 🧭 Custom DNS: Choose between public DNS or encrypted DNS services.
• 📱 Cross-Platform: Works seamlessly on Android and iOS using the same Flutter codebase.

⚙️ Technical Stack (Expertise)

• Frontend: Flutter 3.x (Dart 3, Material 3 design)
• VPN Core: Android VpnService API / OpenVPN / WireGuard client (as supported by the build)
• Backend (optional): Laravel 10 or Node.js API for subscription validation & server listings
• Database: Firebase Firestore or MySQL (via Laravel backend)
• Authentication: Firebase Auth / JWT / Email verification (depending on setup)
• Payments: Google Play Billing (subs) / Apple In-App Purchases
• Ads: Google AdMob, Facebook Audience Network, StartApp SDK
• Push Notifications: Firebase Cloud Messaging (FCM)
• Server Requirements: PHP 8.1+ / Node 18+, HTTPS/TLS 1.2+, MySQL 8+, Nginx or Apache

🧩 Installation Guide

1. Install Flutter SDK and set up your IDE (Android Studio / VS Code).
2. Run flutter pub get to install all dependencies.
3. Configure lib/config.dart with your AdMob, Facebook, and StartApp IDs.
4. Connect Firebase (optional) for push notifications and authentication.
5. Integrate VPN configuration profiles (OpenVPN/WireGuard servers).
6. Customize UI assets (logos, splash screens, colors, etc.).
7. Run flutter build apk --release or flutter build ios for production builds.
8. Deploy backend API (if included) using Laravel or Node.js and set API_BASE_URL.

📦 Deliverables

• ✅ Flutter app source code (Android & iOS)
• ✅ Optional Laravel/Node.js backend with subscription validation
• ✅ Ad network integration templates (AdMob, StartApp, Facebook)
• ✅ Firebase setup files & documentation
• ✅ Example VPN configuration scripts
• ✅ Installation guide + GPL v3 license

📱 Supported Platforms

• Android: 8.0 (API 26) and higher
• iOS: 13+ (Xcode 15+, optional build)
• Server OS: Ubuntu/Debian with OpenVPN or WireGuard configured

👨‍💻 Original Developer Credit

This app template credits the original author from CodeCanyon.
Support the creator via:
CodeCanyon – Original Author.

🔒 Disclaimer

This source code is redistributed under the GPL v3 license for educational and lawful commercial use.
We are not affiliated with any brand or network.
Ensure compliance with your local telecom and data-privacy laws before launching a VPN product.
Always use verified VPN server infrastructure and secure user data responsibly.