🐮 What is CowChat

CowChat is a real-time chat application built with Spring and Angular, designed to provide a modern, responsive, and secure messaging experience.
It combines websocket-based communication, JWT authentication, and RESTful APIs to create a fast, scalable, and user-friendly chat platform.

Users can register, authenticate through JWT, send real-time messages, and manage conversations dynamically, all within an interface optimized for desktop and mobile.

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✨ The system introduces:

• Real-Time Messaging: WebSocket integration for instant communication
• User Authentication: JWT-based session handling with OAuth2 compatibility
• Responsive Design: Fully functional interface across desktop and mobile
• User Presence Tracking: Online/offline status updates for active users
• Persistent Storage: Messages and user data stored securely in PostgreSQL
• Persistent Images: Profile images are stored in AWS (S3 buckets)
• Role System: Permissions and access levels managed through Spring Security
• Modern UI: Angular frontend styled with Tailwind CSS for speed and aesthetics

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🧰 Technologies Used in CowChat

Backend

• Java → Runtime environment
• Spring → Backend framework and dependency injection
• Spring WebSocket → Real-time bidirectional communication
• Spring Security → Authentication and authorization
• JJWT → JSON Web Token handling
• Spring Data JPA + PostgreSQL → ORM and data persistence
• Amazon S3 → Cloud storage for user-uploaded media (e.g., images, files)
• Docker → Containerized environment for backend and database
• AWS EC2 → Cloud server for deployment
• Lombok 1.18.32 → Boilerplate code reduction
• Maven → Build and dependency management
• Postman → API testing and documentation

Frontend

• Angular → Frontend framework
• TypeScript → Strongly-typed JavaScript superset
• RxJS → Reactive event handling
• WebSocket Client → Real-time connection to the backend

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💡 Key Features

Authentication & Authorization

• JWT authentication with refresh token rotation

Real-Time Chat System

• WebSocket integration for low-latency messaging
• User presence tracking (online/offline)
• Message persistence and delivery confirmation
• Private chats and future support for group chats

Frontend Experience

• Clean, responsive UI
• Reactive user list and message feed
• User-friendly interface for mobile and desktop

Technical Highlights

• RESTful API design following clean architecture
• Exception handling with @ControllerAdvice
• DTO conversion through manual mappers
• Comprehensive validation and error responses
• Optimized performance using reactive programming

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Architecture

Messaging system

Built to feel lightweight, fast and responsive across desktop and mobile devices.