Nexis

Real-time file sharing across web and mobile platforms

Nexis is a full-stack application that enables seamless file sharing and real-time communication between web and mobile clients. Built with modern technologies and WebSocket connections, it delivers a smooth, cross-platform experience for sharing files of any size.

✨ Features

• 🔄 Real-time synchronization - Instant file transfers powered by WebSockets
• 📱 Cross-platform support - Works seamlessly on web browsers and mobile devices
• 📦 Chunked file transfers - Smart file splitting for reliable large file handling
• 👥 Session-based sharing - Multi-user sessions with easy connection management
• ⚡ Live progress tracking - Real-time transfer status and progress indicators
• 🔗 Instant connectivity - No account creation required, just share and go

🛠️ Tech Stack

Backend

• Node.js - JavaScript runtime
• Express - Web application framework
• Socket.IO - Real-time bidirectional communication

Frontend

• React - Modern web interface
• Vite - Fast development and build tool

Mobile

• React Native - Cross-platform mobile development
• Expo - Development platform and tools

🏗️ Architecture

nexis/
├── backend/          # Node.js + Socket.IO server
├── web/             # React frontend client
└── mobile/          # React Native mobile app

🌐 Live Deployment

Platform	URL	Status
Web App	nexis-share.netlify.app	🟢 Live
API Backend	nexis-api.railway.app	🟢 Live
Mobile App	Download APK / iOS TestFlight	In Progress

Deployment Details

• Backend: Deployed on Railway (Port 4000)
• Frontend: Deployed on Netlify (Port 5173 in development)
• Mobile: Expo development server (Port 8080)

🚀 Quick Start

Prerequisites

• Node.js (v16 or higher)
• npm or yarn
• Expo CLI (for mobile development)

Backend Setup

cd backend
npm install
npm run dev
# Server runs on http://localhost:4000

Web Client Setup

cd web
npm install
npm run dev
# Client runs on http://localhost:5173

Mobile App Setup

cd mobile
npm install
npx expo start
# Metro bundler runs on http://localhost:8080

📖 How It Works

1. Session Creation - Users create or join sharing sessions
2. File Selection - Choose files from device storage
3. Chunked Transfer - Files are split into manageable chunks
4. Real-time Sync - WebSocket connections ensure instant updates
5. Progress Tracking - Live progress bars show transfer status
6. File Reconstruction - Chunks are reassembled on the receiving end

🔧 Configuration

The application currently runs with default configurations. Backend connects on port 4000, web client on port 5173, and mobile development server on port 8080.

📱 Mobile App Distribution

Android

• Download APK from Releases
• Install via adb install nexis.apk

iOS

• Join TestFlight beta program
• Install via Expo Go for development

🧠 Technical Deep Dive

File Chunking Algorithm

const CHUNK_SIZE = 64 * 1024; // 64KB chunks
// Files are split into manageable pieces to prevent memory overflow
// and enable resumable transfers

WebSocket Events

• join-session - Connect to sharing session
• file-chunk - Transfer file piece
• transfer-progress - Update progress status
• transfer-complete - Signal successful completion

Error Handling

• Automatic reconnection for dropped connections
• Chunk validation and retry mechanisms
• Progress state persistence across interruptions

🎯 What I Learned

Building Nexis was a comprehensive journey into real-time systems and cross-platform development:

• WebSocket Mastery - Deep understanding of bidirectional communication patterns
• File Handling - Efficient chunked transfer algorithms for large files
• Cross-Platform Development - Unified codebase strategies for web and mobile
• Deployment Architecture - Modern CI/CD practices with Railway and Netlify
• Real-time State Management - Synchronizing state across multiple clients

The chunked file transfer implementation was particularly challenging and rewarding. Instead of attempting to send entire files (which fails for large files and poor connections), I developed a robust system that:

• Splits files into 64KB chunks
• Transfers chunks with progress tracking
• Handles network interruptions gracefully
• Reassembles files with integrity verification

🤝 Open for Collaboration

This project is open for collaboration and new ideas! Whether you're interested in contributing code, suggesting features, or discussing improvements, I'd love to hear from you.

Ways to get involved:

• 💡 Share ideas for new features or improvements
• 🐛 Report bugs or issues you encounter
• 🚀 Submit pull requests with enhancements
• 📝 Improve documentation or add examples
• 🎨 Contribute to UI/UX design improvements

Feel free to open an issue to start a discussion or reach out if you want to collaborate on making Nexis even better!