# YSNRFD Messenger

A modern, real-time messaging application built with the MERN stack (MongoDB, Express.js, React, Node.js) and Socket.IO.

## 🚀 Features

### Core Messaging
- Real-time one-on-one and group messaging
- Read receipts and typing indicators
- Message status (sending, sent, delivered, read)
- Message editing and deletion
- Emoji reactions

### File Sharing
- Image files with preview and download
- Audio files with built-in player
- Document files (PDF, TXT) with download
- File size validation and type checking
- Drag & drop file upload

### User Experience
- Dark/Light theme support
- Responsive design for all devices
- Progressive Web App (PWA) support
- Auto-login with token persistence
- Online/offline status
- User search and contact management

### Advanced Features
- Group chats with admin roles
- Invite links for group joining
- Message search and filtering
- File caching for offline access
- Real-time notifications
- Cross-device synchronization

## 🛠️ Tech Stack

### Frontend
- **React 18** with TypeScript
- **Tailwind CSS** for styling
- **Socket.IO Client** for real-time communication
- **Vite** for build tooling
- **Lucide React** for icons

### Backend
- **Node.js** with Express.js
- **Socket.IO** for WebSocket communication
- **MongoDB** with Mongoose ODM
- **JWT** for authentication
- **Multer** for file uploads

## 📦 Installation

### Prerequisites
- Node.js 16+ 
- MongoDB 4.4+
- npm or yarn

### Backend Setup
```bash
cd backend
npm install
cp .env.example .env
# Configure your environment variables
npm run dev
```