Full-Stack • Java/Spring Boot • React & React Native • Cloud & AI

Hi, I'm Kumaresan Kajarajithan

Also known as Kajan • Software Engineer

Software Engineer with hands-on experience in full-stack development, mobile application development, backend API engineering, and software quality assurance.

View Featured Projects Contact & Resume

Backend Core

Java, Spring Boot, Node.js, PostgreSQL, JWT & RBAC

Web & Mobile

React.js, Next.js, React Native (Expo), Flutter

Cloud & QA

Azure Ubuntu VM, GitHub Actions, Postman, Selenium

SYS.CORE // STATIC MODE

Architecture Core View

Introduction

Engineering Discipline Across Backend, Client & QA

Combining academic rigor in Applied Computing with hands-on software development and quality assurance.

Software Engineer with hands-on experience in full-stack development, mobile application development, backend API engineering, and software quality assurance.

Skilled in Java, Spring Boot, React.js, React Native, TypeScript, REST APIs, and PostgreSQL. Experienced in secure backend systems, JWT authentication, role-based access control, API integration, testing, and Azure deployment.

Interested in building scalable and maintainable software solutions across web, mobile, and cloud platforms.

BSc (Hons) Applied Computing

University of Jaffna

Full-Stack Architecture

Spring Boot, PostgreSQL, React, React Native & MERN

Dual Internship Experience in Dev, AI & QA

AI Engineering (Development & QA) at Samuel Gnanam IT Centre and Software/QA at Techorin.

Featured Work

Selected Engineering Projects

End-to-end applications built with Spring Boot, React, React Native, Next.js, PostgreSQL, Azure, and MERN.

All Projects

Full-Stack & Mobile Full-Stack & Mobile Engineer

Architecture & Case Study Ready • Screenshot slot available in static/projects/

2 Slots

Defect Tracking System & Mobile Application

Unified Full-Stack Web & Cross-Platform Mobile Issue Lifecycle Platform

Developed a full-stack defect management platform supporting project workflows, defect tracking, secure authentication, role-based access control, project dashboards, defect filtering, risk analysis, and data visualization across both web and mobile clients.

Architecture Flow

3 Layers

Java & Spring Boot REST API + JWT/RBAC → PostgreSQL | Clients: React.js Web & React Native (Expo + TypeScript)

JavaSpring BootPostgreSQLReact.jsReact NativeExpoTypeScriptJWTREST APIs

Explore Architecture & Case Study

Full-Stack Web Full-Stack Developer

Architecture & Case Study Ready • Screenshot slot available in static/projects/

2 Slots

GK Tennis Academy Management System

Court Booking, Coaching & Tournament Operations Platform

Developed a tennis academy management platform supporting court bookings, coach scheduling, tournament management, player registration, role-based access control, payment workflows, and real-time booking availability.

Architecture Flow

3 Layers

Next.js + React + TypeScript (Tailwind CSS) → Supabase & PostgreSQL (RBAC, Bookings & Tournaments)

ReactNext.jsTypeScriptSupabaseTailwind CSSPostgreSQL

Explore Architecture & Case Study

Full-Stack Web (MERN) Full-Stack MERN Developer

Architecture & Case Study Ready • Screenshot slot available in static/projects/

2 Slots

Channeling Center Management System

MERN Stack Healthcare Appointment, Patient Records & Pharmacy Inventory Platform

Developed a healthcare appointment and management system supporting patient records, medical histories, medicine inventory, role-based access control, and online payments.

Architecture Flow

3 Layers

React.js + Tailwind CSS → Node.js & Express.js REST API (RBAC & Payments) → MongoDB

MongoDBExpress.jsReact.jsNode.jsTailwind CSS

Explore Architecture & Case Study

Mobile & Full-Stack Mobile & Full-Stack Developer

Architecture & Case Study Ready • Screenshot slot available in static/projects/

1 Slot

Expense Tracker Mobile Application

Cross-Platform Flutter & Node.js Personal Finance Platform

Developed a full-stack mobile expense tracking application with expense management, REST API integration, persistent storage, real-time synchronization, and modular architecture.

Architecture Flow

3 Layers

Flutter & Dart Mobile Client ↔ REST APIs ↔ Node.js & Express.js ↔ MongoDB Persistent Store

FlutterDartNode.jsExpress.jsMongoDBREST APIs

Explore Architecture & Case Study

Full-Stack & Cloud Full-Stack Developer

Architecture & Case Study Ready • Screenshot slot available in static/projects/

1 Slot

Library Management System

Cloud-Deployed Student, Catalog & Circulation Management Platform

Developed a full-stack library management system with student/book management, borrowing and returning workflows, REST API integration, and automated deployment.

Architecture Flow

3 Layers

React & TypeScript → Java & Spring Boot REST API → PostgreSQL | CI/CD: GitHub Actions → Azure

JavaSpring BootReactTypeScriptPostgreSQLGitHub ActionsAzure

Explore Architecture & Case Study

Technical Stack

Core Technologies & Capabilities

Focused on Java/Spring Boot backend services, modern React/React Native interfaces, cloud CI/CD, and software quality.

Full Skills Matrix

Java

Programming Languages

Object-oriented backend engineering, Spring Boot services, and enterprise domain logic

TypeScript

Programming Languages

Type-safe frontend, Next.js, and React Native / Expo mobile engineering

React.js

Frontend & Mobile

Interactive dashboards, data visualization, and full-stack web client portals

Next.js

Frontend & Mobile

Full-stack React framework for booking, scheduling, and management systems

React Native & Expo

Frontend & Mobile

Cross-platform mobile applications integrated with secure REST APIs

Flutter

Frontend & Mobile

Modular cross-platform mobile interfaces with real-time REST synchronization

Spring Boot

Backend

Enterprise REST APIs, layered service architecture, and security integration

Node.js & Express.js

Backend

RESTful backend services for MERN and mobile applications

REST APIs

Backend

Contract design, CRUD operations, filtering, and client-server integration

PostgreSQL

Databases

Relational schema design, transactional integrity, and production cloud persistence

MongoDB

Databases

Document data modeling for healthcare and expense tracking platforms

Microsoft Azure

DevOps & Tools

Azure Ubuntu VM provisioning, PostgreSQL hosting, and systemd service deployment

Postman

DevOps & Tools

Functional, API, integration, and regression testing of REST endpoints

JWT Authentication & RBAC

Core Concepts

Stateless JWT security and Role-Based Access Control across web and mobile apps

Software Testing & QA

Core Concepts

Test case design, bug identification, defect reporting, and regression verification

Industry Experience

Internships & Engineering Roles

Hands-on experience across AI Engineering, Full-Stack Development, and Software Quality Assurance.

Detailed Timeline

Internship

Intern AI Engineer (Development & QA)

Samuel Gnanam IT Centre, Sri Lanka

May 2026 – October 2026

Sri Lanka

Engineered a full-stack and mobile Defect Tracking System while executing comprehensive API, functional, regression, and automated QA workflows and managing cloud deployment on Azure.

JavaSpring BootPostgreSQLREST APIsJWTReact NativeExpoTypeScriptPostmanSelenium WebDriverAzure Ubuntu VMsystemd

Internship

Intern Software Engineer

Techorin, Sri Lanka

November 2025 – March 2026

Sri Lanka

Focused on software quality assurance processes, structured test case preparation, defect lifecycle reporting, and industry-standard testing methodologies.

Software Quality Assurance (QA)Test Case DesignDefect ReportingQuality VerificationSoftware Testing Methodologies

Open for Software Engineering Opportunities

Looking for an Associate / Junior Software Engineer, Full-Stack, or Backend Developer?

Explore my project architecture breakdowns or reach out directly at k.kajan2001@gmail.com to discuss full-stack, mobile, and backend engineering roles.

Get in Touch Download Resume