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Brian De Jesus / Software Developer / Germany

Web applications, APIs, and the work behind them.

I work with C# and .NET on API integrations and internal tools. Outside work, I build full-stack applications with React, Node.js, and PostgreSQL.

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Craft
C# / .NET / SQL
Systems
APIs / Automation
Products
React / Node.js

Selected projects

From a practical need to a working application.

Independent projects developed in my free time, outside my employment. Each project below explains what I built and its current status.

Client project · Deployed · Payments in sandbox

Virtus

A vehicle rental platform covering reservations, vehicle availability, customer registration, contracts, invoices, and vehicle check-in and check-out.

I built the frontend and backend, including Supabase Auth, role-based access, and Stripe integration with webhooks. The app is deployed; Stripe payments are currently in sandbox while production activation is pending.

Stack: React 18 · Tailwind CSS · Vite · Express.js · Supabase / PostgreSQL

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Sumitomo Benkyo dashboard with flashcard review, card totals, and quick actions
Personal project · Deployed · Ongoing development

住友勉強 (Sumitomo Benkyo)

A language-learning app I started to help my fiancée learn English vocabulary, with multilingual flashcards, spaced repetition, and AI-powered language and speech features.

I built the web app and backend, integrated OpenAI and Whisper, and prepared an iOS version with Capacitor. I continue improving the app's reliability and learning experience.

Stack: React · TypeScript · Vite · Node.js / Express.js · Supabase · Capacitor

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Technologies

Technologies I use at work and in my projects.

Frontend

React, TypeScript, AngularJS, and Next.js

Backend

C# and .NET for business logic

Data

SQL Server, PostgreSQL, and Supabase

Integrations

REST APIs, Stripe webhooks, and OpenAI APIs

Tools

Git, Docker, Azure, Vercel, and Render

My approach

How I approach development.

“Understand the problem first.”

I start with the information people need and the workflow they follow, whether that means preparing customer offers or managing rental reservations.

“Make integrations useful.”

My work connects external services to applications, then makes the resulting data accessible through APIs and interfaces.

“Keep learning through real projects.”

I learn by building, tracing bugs, asking for feedback, and improving existing features. I use Claude and Codex to support coding, debugging, and documentation.

Backend DevelopmentFull-Stack ApplicationsDebugging & MaintenanceAPI Integrations

About me

Hi, I'm Brian.

I am a software developer based near Hamburg, completing my software development apprenticeship at ETA PLUS. My day-to-day work focuses on C#/.NET, SQL, API integrations, and AngularJS/TypeScript.

Sumidev is my personal portfolio. Outside my working hours, I develop client and personal projects to solve practical problems and explore new technologies. I am interested in junior backend and full-stack opportunities after my apprenticeship.

Current role

Software development apprentice at ETA PLUS

Developing C#/.NET API integrations and AngularJS/TypeScript interfaces, and troubleshooting imports, API issues, and frontend bugs.

Outside work

Independent full-stack projects

Building Virtus for vehicle rental management and Sumitomo Benkyo for language learning in my free time.

January 2027

Expected apprenticeship completion

Completing my German vocational qualification in software development (Fachinformatiker für Anwendungsentwicklung, IHK).

Contact

Let's talk.

Have a question about my projects or a backend or full-stack opportunity? Send me a message. I expect to complete my apprenticeship in January 2027.