Raj Kumar Sony
Java Backend Engineer building scalable cloud systems
New to Contra
Raj Kumar is ready for their next project!
Task Management System 🚀
Designed and developed a modern task management platform that helps teams plan, organize, collaborate, and track work in real time. The application streamlines project execution through intuitive task management, Kanban workflows, team collaboration, reporting, deadline tracking, and real-time notifications. Built with a cloud-native architecture, it provides a secure, scalable, and high-performance solution that enables organizations to manage multiple projects, improve team productivity, and monitor progress from a centralized dashboard across desktop and mobile devices.
🧑💻 What I built:
• Project and workspace management
• Task creation, assignment, and prioritization
• Kanban board and list-based workflows
• Team collaboration and member management
• Real-time dashboard and analytics
• Calendar and deadline management
• File attachments and task comments
• Activity timeline and audit history
• Role-based access control (RBAC)
• Real-time notifications and alerts
• Responsive web and mobile interface
🧠 Engineering Highlights
• Designed a scalable microservices-based architecture for enterprise workloads
• Optimized dashboard queries using caching and efficient database indexing
• Built real-time collaboration using event-driven communication
• Implemented secure authentication with Spring Security and JWT
• Developed modular RESTful APIs following clean architecture principles
• Containerized the application using Docker for consistent deployments
• Cloud-ready architecture optimized for AWS infrastructure
• Built for horizontal scalability, maintainability, and high availability
🛠️ Tech Stack:
Java 21 • Spring Boot • React • PostgreSQL • Redis • REST APIs • Spring Security • JWT • Docker • AWS • OpenAPI/Swagger
Status: Completed ✅
0
20
Rate Limiter as a Service ⚡
Designed and developed a production-grade Rate Limiter as a Service that protects APIs from abuse, controls request traffic, and ensures fair resource utilization across distributed applications. The platform enables developers to define flexible rate limiting policies, monitor API consumption in real time, and enforce request quotas with minimal latency. Built using a cloud-native architecture, it supports multiple rate limiting algorithms, horizontal scaling, and high availability, making it suitable for modern microservices and enterprise API platforms.
🧑💻 What I built:
• API key, client, user, and IP-based rate limiting
• Configurable rate limiting policies
• Sliding Window, Fixed Window, and Token Bucket algorithms
• Real-time request monitoring dashboard
• Client usage analytics and reporting
• Rate limit utilization tracking
• Alert management for unusual traffic
• REST APIs for policy administration
• Secure API authentication and authorization
• Responsive web dashboard for monitoring and management
🧠 Engineering Highlights
• Built a distributed rate limiting system using Redis for high-speed request tracking
• Designed stateless services for horizontal scalability across multiple instances
• Optimized request validation with low-latency in-memory operations
• Implemented configurable throttling strategies for different client requirements
• Secure authentication using Spring Security and JWT
• Cloud-ready deployment with Docker and AWS
• Fault-tolerant architecture with graceful degradation during high traffic
• Production-ready modular architecture following clean coding principles
🛠️ Tech Stack:
Java 21 • Spring Boot • Redis • PostgreSQL • REST APIs • Spring Security • JWT • Docker • AWS • OpenAPI/Swagger
Status: Completed ✅
0
23
Social Feed Platform 🌐
Designed and developed a modern social networking platform that enables users to connect, share content, engage with communities, and communicate in real time. The application provides personalized news feeds, user profiles, post creation, social interactions, trending content discovery, and instant notifications through a responsive and intuitive interface. Built using a cloud-native architecture, it delivers high performance, security, scalability, and a seamless user experience across desktop and mobile devices.
🧑💻 What I built:
• User registration and secure authentication
• Personalized user profiles
• Create, edit, and delete posts
• Like, comment, and share functionality
• Follow and unfollow users
• Personalized social feed
• Trending hashtags and content discovery
• User and post search
• Real-time notifications using WebSocket
• Responsive web and mobile interface
🧠 Engineering Highlights
• Designed with a scalable microservices architecture
• Real-time communication using WebSocket
• Optimized data retrieval with Redis caching
• Secure authentication using JWT and Spring Security
• RESTful APIs with clean layered architecture
• Cloud-ready deployment using Docker and AWS
• High-performance backend built for enterprise-scale workloads
• Production-ready architecture with modular and maintainable codebase
🛠️ Tech Stack:
Java 21 • Spring Boot • React • PostgreSQL • Redis • WebSocket • REST APIs • Spring Security • JWT • Docker • AWS
Status: Completed ✅
0
32
URL Shortener + Analytics 🔗
Designed and developed a production-grade URL shortening platform that transforms long URLs into secure, shareable short links while providing powerful real-time analytics and performance insights. The platform enables users to create custom short URLs, monitor click activity, analyze visitor behavior, and manage thousands of links through an intuitive dashboard. Built using a cloud-native, event-driven architecture, it delivers high availability, low-latency redirects, and scalable analytics processing for enterprise-scale applications.
🧑💻 What I built:
• Generate secure and unique short URLs
• Custom aliases and branded short links
• Real-time click tracking and analytics
• Geographic and device-based insights
• Browser and operating system analytics
• Referrer and traffic source tracking
• QR code generation for every short URL
• Link management dashboard
• Search, filter, and organize links
• REST APIs for seamless integration
🧠 Engineering Highlights
• Implemented high-speed redirects using Redis caching
• Asynchronous analytics processing with Apache Kafka
• Designed a scalable event-driven architecture for millions of requests
• Optimized database performance with indexing and query tuning
• Secure authentication using Spring Security and JWT
• Built RESTful APIs following clean architecture principles
• Cloud-ready deployment with Docker and AWS
• Enterprise-grade architecture focused on scalability, reliability, and maintainability
🛠️ Tech Stack:
Java 21 • Spring Boot • PostgreSQL • Redis • Apache Kafka • REST APIs • Spring Security • JWT • Docker • AWS • OpenAPI/Swagger
Status: Completed ✅
0
6
Task Management System 🚀
Designed and developed a modern task management platform that helps teams plan, organize, collaborate, and track work in real time. The application provides project management, task assignment, progress monitoring, reporting, and notifications through an intuitive dashboard while maintaining high performance, security, and scalability. Built using a cloud-native architecture, it supports multiple teams, role-based access, and seamless collaboration across projects.
🧑🔧 What I built:
• Project and task management
• Kanban & list-based workflows
• Team collaboration and task assignment
• Real-time dashboard and reporting
• Calendar and deadline management
File attachments and comments
• Activity timeline and audit history
• Role-based access control (RBAC)
• Real-time notifications
• Responsive web and mobile interface
🧠 Engineering Highlights
• Designed with a scalable microservices architecture
• Optimized dashboard queries for fast response times
• Real-time updates using event-driven communication
• Secure authentication with JWT and role-based authorization
• Cloud-ready deployment with containerized services
• Built for horizontal scaling and enterprise workloads
🛠️ Tech Stack:
Java 21 • Spring Boot • PostgreSQL • React • REST APIs • Spring Security • JWT • Docker • AWS
Status: Completed ✅
0
46