Hi, I'm
Larryck Ontsandaga

Student Backend Software Engineer designing and building scalable, high-performance systems. Specializing in microservices, and distributed systems. Passionate about writing clean, maintainable code and solving complex technical challenges.

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About Me

Background & Expertise

Professional Overview

I am a backend-focused software engineering student with hands-on experience designing and building robust applications using Spring Boot and modern Java. My expertise spans full-stack development, with a focus on backend architecture, RESTful API design, and database management.

Through my projects, I have developed production-ready applications with secure authentication, payment integrations, and real-time features. I am committed to writing clean, maintainable code and continuously learning new technologies through practical implementation.

Key Strengths

  • Backend Development: Build scalable REST APIs with Spring Boot, security, and data persistence
  • API Development: Design and implement RESTful APIs with comprehensive documentation
  • Database Management: Schema design, SQL optimization, and Flyway migrations
  • Authentication & Security: JWT, OAuth2, password hashing, and secure session management
  • Code Quality: Strong advocate for testing, documentation, and clean code practices
  • Full-Stack Skills: Experience with both backend APIs and frontend development

Technical Stack

Core Competencies

A comprehensive overview of programming languages, frameworks, databases, and tools I use to build production-grade backend systems.

Languages & Frameworks

Java
Spring Boot / Spring Framework
Node.js / Express.js
Python
PHP
JavaScript / React

Databases & Data

MySQL
PostgreSQL
Flyway Migrations

Cloud & DevOps

Git / Version Control
GitHub
Shell Scripting

Tools & Practices

Git / Version Control
Testing (Unit, Integration, E2E)
API Design (REST, GraphQL)
Microservices Architecture
Agile / Scrum Methodologies

Portfolio

Featured Projects

A selection of backend projects that showcase system design, scalability, and technical excellence.

E-Commerce

E-Commerce REST API

Java 21 Spring Boot 3.5 MySQL JWT & OAuth2 Stripe & PayPal

Robust REST API for e-commerce platform with secure authentication, product management, shopping cart functionality, and payment integration. Features JWT-based security, role-based access control, and multi-provider payment processing.

Key Features:

  • JWT & OAuth2 authentication (Google, GitHub social login)
  • Product catalog with search, filtering, and category management
  • Shopping cart with dynamic pricing
  • Stripe & PayPal payment gateway integration
  • Email-based password reset functionality
  • Role-based access control (Admin/User)
GitHub
Backend

Movie Reservation System

Java 21 Spring Boot 3.5 PostgreSQL JWT Flutterwave API

Comprehensive movie theater reservation platform with user management, movie catalog, theater scheduling, and integrated payment processing. Implements seat locking mechanisms to prevent double-booking and supports card payments with Flutterwave integration.

Technical Highlights:

  • Multi-screen theater management with configurable seat layouts
  • 5-minute seat locking to prevent double-booking
  • Flutterwave payment integration (Cards, Mobile Money)
  • 16+ Flyway database migrations
  • Automatic cleanup of expired locks and pending tickets
  • Comprehensive API with pagination and filtering
GitHub
Full-Stack

To-Do List Application

Java 21 Spring Boot 3.5 MySQL JWT HTML/CSS/JS

Full-stack web application for personal task management with secure authentication and session management. Features JWT-based security with HTTP-only cookies, responsive UI, and complete CRUD operations for todo items with persistent data storage.

Key Features:

  • User registration and authentication with JWT tokens
  • HTTP-only cookie-based session management
  • Complete CRUD operations for tasks
  • Secure logout with server-side session invalidation
  • Password encryption with BCrypt
  • Responsive and intuitive user interface
GitHub
Real-Time

Messaging Application

Java Spring Boot WebSocket/STOMP Real-Time Communication

Real-time messaging application leveraging WebSocket and STOMP protocol for bidirectional communication. Demonstrates advanced Spring Boot features for building interactive, real-time systems with efficient message delivery and user session management.

Technical Implementation:

  • WebSocket and STOMP protocol implementation
  • Real-time message broadcasting to users
  • Session management and user presence tracking
  • Message history and persistence
  • Scalable architecture for concurrent connections
GitHub
Service

HandyGuys Services Platform

Java Spring Boot React Full-Stack

Full-stack service marketplace platform connecting service providers with customers. Developed both backend REST APIs and frontend React application, demonstrating complete software development lifecycle from design through deployment.

Project Scope:

  • RESTful API for service management and booking
  • User authentication and authorization
  • Service provider profiles and ratings
  • Booking and payment management
  • React-based responsive frontend UI
Backend Frontend
Community

Lost & Found Platform

PHP Web Platform Community

Web-based platform designed to help communities reunite lost items with their owners. Features item listing, search functionality, and community engagement capabilities to facilitate item recovery and community connection.

Platform Features:

  • Post lost or found items with descriptions
  • Advanced search and filtering capabilities
  • Item categorization and geolocation tracking
  • User messaging and communication system
  • Community-driven verification and matching
GitHub

Career Path

Professional Experience

Software Engineering Student & Full-Stack Developer

Self-Directed Learning & Open Source 2024 – Present

Active software developer building production-grade applications across full-stack and backend domains, focusing on system design, security, and scalability.

  • Architected and developed 6+ production backend systems with Spring Boot and modern Java
  • Implemented comprehensive e-commerce platform with payment gateway integration (Stripe, PayPal)
  • Built movie reservation system with seat locking mechanism, preventing race conditions and double-booking
  • Designed real-time messaging application using WebSocket and STOMP protocol
  • Developed full-stack applications demonstrating end-to-end development lifecycle
  • Practiced security best practices: JWT authentication, OAuth2, password hashing, and encryption

Technical Skills Development & Specialization

Continuous Learning 2024 – Present

Deepening expertise in backend technologies and system design through hands-on projects and modern development practices.

  • Mastered Spring Boot 3.x with advanced features: Security, Data JPA, and custom configurations
  • Implemented database design patterns: Entity relationships, migrations (Flyway), indexing, and optimization
  • Worked with multiple databases: MySQL, PostgreSQL, and relational data modeling
  • Integrated third-party APIs: Stripe, PayPal, Flutterwave for payment processing
  • Built RESTful APIs with comprehensive documentation and CRUD operations
  • Established testing practices and deployment methodologies

Project-Based Experience & Problem Solving

Portfolio Projects 2024 – Present

Building diverse applications to solve real-world problems and develop practical software engineering skills.

  • Developed to-do management system with secure authentication and session management
  • Created service marketplace platform (HandyGuys) with both backend and frontend components
  • Built community platform (Lost & Found) for item recovery and connection
  • Implemented comprehensive feature sets including payment processing, user management, and business logic
  • Followed best practices: Code organization, error handling, validation, and documentation

Education

Academic Background

Bachelor of Science in Software Engineering

Adventist University of Central Africa Graduated: December 2026

GPA: 3.15 | Relevant Coursework: Data Structures, Algorithms, Database Systems, Operating Systems, Software Engineering, Object-Oriented Programming, Web Development

Focus: Backend development, system design, and full-stack application development

Get In Touch

Let's Collaborate

I'm always interested in hearing about new projects, opportunities, and technical challenges. Feel free to reach out!

Contact Information

Get in touch through any of these channels.

Email

rancyontsandaga@gmail.com

Phone

+250 785 511 304

Location

Kigali, Rwanda

Connect With Me