SOFTWARE ENGINEER

Building production-grade web, mobile, and cloud backend solutions with .NET, React, React Native, and Supabase. Clean architecture, high performance, and great user experience.

5+

Years Experience

3+

Projects Shipped

sebastian@portfolio:~
$ whoami

Sebastian De Leon — Computer Engineering Student @ WMU

$ cat stack.txt

languages TypeScript · JavaScript · C# · Python · SQL · C · C++

frontend  Next.js · React · React Native · Tailwind CSS

backend   ASP.NET Core (.NET 9) · CQRS · DDD · EF Core

mobile    React Native · Expo · Jetpack Compose

database  PostgreSQL · MS SQL Server · Supabase

devops/toolsGit · Docker · Linux · Edge Functions

$ echo $status

Open to new opportunities ✓

█

Experience

Reispsolutions S.R.L.

Reispsolutions S.R.L.

Junior Software Engineer

  • ▸Architected a distributed Learning Management System (LMS) for a multi-brand restaurant corporation in the Dominican Republic, scaling training infrastructure across dozens of branch locations using ASP.NET.
  • ▸Built production-oriented ASP.NET Core services with .NET 9, CQRS, DDD, and Clean Architecture, implementing controllers, application services, domain models, and EF Core persistence across multiple backend services.
  • ▸Developed an end-to-end clinical management web application that automated patient intake flows, integrated calendar scheduling, and deployed automated SMS/email reminders for upcoming appointments.
Apolo 27 (INTEC — NASA HERC Team)

Apolo 27 (INTEC — NASA HERC Team)

Manufacturing & Telemetry Assistant

  • ▸Designed and implemented Task A for the 2025 NASA HERC rover: a lead-screw actuator driven by a stepper motor that moved a sensor vertically to detect whether a container holding liquid contained water.
  • ▸Built the rover control system around an ESP32-S3, reading PWM signals from a commercial RC receiver and implementing a state machine to map controller inputs to rover motion and task execution.
  • ▸Led the full-stack architecture for the official Apolo 27 website, including frontend and backend development.
  • ▸Managed the development of proprietary games and digital tools for STEM outreach across the Dominican Republic.

Projects

Velo: Movie Matchmaker
Velo: Movie Matchmaker
Velo: Movie Matchmaker

Velo: Movie Matchmaker

Cross-platform Expo/React Native movie matchmaking app with Clean Architecture, Zustand, Supabase Realtime, weighted voting, veto logic, and multi-language support.

React NativeExpoTypeScriptZustandSupabase
Printune
Printune

Printune

Full-stack Next.js/FastAPI tool converting Spotify track, album, and playlist URLs into personalized 3D-printable keychains with Three.js orbit previews and STL export.

Next.jsTailwind CSSThree.jsPythonFastAPI
Apolo 27 Website 2024 & 2025

Apolo 27 Website 2024 & 2025

Official website for the Apolo 27 team competing at NASA's Human Exploration Rover Challenge (HERC).

Next.jsTailwind CSS
Clinical Management System

Clinical Management System

End-to-end clinical management application automating patient intake flows, calendar scheduling, and automated SMS/email reminders.

ReactTailwind CSSMongoDBExpressNode.js
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Minevers

Interactive web tool to explore and compare new features, biomes, and changes across Minecraft versions.

React