Open to remote backend roles

Vijay Kumar

Java Backend Engineer

Spring Boot 3 · WebSocket · PostgreSQL · Java 17

Built Nexus — a live real-time multiplayer platform with STOMP WebSocket sessions, concurrent game state, and automated CI/CD to Oracle Cloud.

View Live Project ↗ View Resume →
Vijay Kumar — Java Backend Engineer

Background

About Me

Vijay Kumar working

Experience

Independent Backend Engineer

Education

MCA · BCA

Backend engineer with production experience building real-time distributed systems using Java 17 and Spring Boot 3. Designed and shipped Nexus — a live multiplayer game platform with STOMP WebSocket sessions, PostgreSQL persistence, and automated CI/CD via GitHub Actions. Focused on clean architecture, concurrency, and systems that hold up under real user load. Actively contributing to open-source and targeting remote backend engineering roles.

Technical Expertise

Stack

Core & Backend

  • Java 1790%
  • Spring Boot 385%
  • Spring Data JPA80%
  • WebSocket / STOMP85%
  • PostgreSQL78%
  • DSA88%

Tools & Infrastructure

  • Git & GitHub92%
  • GitHub Actions78%
  • Docker68%
  • Linux (Ubuntu)78%
  • Maven / JUnit75%
  • REST APIs90%

What I've Built

Projects

Live
Nexus Multiplayer Arena project screenshot showing real-time game interface
Java 17 · Spring Boot 3 · WebSocket (STOMP/SockJS) · PostgreSQL

Nexus Multiplayer Arena

Real-time multiplayer game platform with STOMP WebSocket sessions, bcrypt authentication, email activation via Resend HTTP API, and automated CI/CD via GitHub Actions to Oracle Cloud.

  • Concurrent game state managed in ConcurrentHashMap — no race conditions under load
  • Diagnosed Railway port-587 SMTP block; replaced with Resend HTTP API for reliable email delivery
  • Fixed JPQL enum inner-class crash causing move rejections every 10 seconds
  • WebSocket session lifecycle with connect/disconnect presence tracking
Live Demo ↗ GitHub
TicTacToe network multiplayer game
Java · Sockets · Multithreading

TicTacToe (Network Multiplayer)

Network-based multiplayer game using raw Java Sockets. Handles concurrent sessions with dedicated threads. Architectural predecessor to Nexus.

GitHub ↗
Data Structures and Algorithms implementations in Java
Java 17 · Algorithms · Data Structures

DSA In Java

Documented implementations of Trees, Graphs, Linked Lists, and sorting algorithms. Each solution includes verified time and space complexity analysis with test cases.

GitHub ↗

Writing

Engineering Log

View all entries

Get In Touch

Contact

Open to remote backend engineering roles.
Reach out — I reply within 24 hours.

vkumar.kumar31@gmail.com linkedin.com/in/vijaykumarcode