Hello. I am Stefan, a freelance software developer with more than 25 years of professional experience, based in Berlin.

Are you looking for help? I'm available for contract work with React.js, Node.js, TypeScript, and AI-based coding.

Experience

I have spent the last 9 years working with React.js, Node.js, and TypeScript for enterprise scale customers and startups. Before that, I have worked with C++, Java, and Ruby on Rails for many years.

I have more than 25 years of professional experience. I have co-founded two companies, worked as a CTO, team lead, and lead developer, and have written two books about Java. I have coached individuals and teams. I am also a Certified Scrum Master.

In recent projects I use agentic coding tools like Claude Code and Cursor to ship features faster.

Skills

TypeScript

React.js

Node.js

AI

Scrum

Testimonials

I have some customer testimonials on LinkedIn.

Portfolio

Recto

WEB APP · PRODUCT ENGINEERING

A visual flat-plan tool for print designers that maps a publication the way books are actually made — pages, spreads, and print sheets — built with React, TypeScript, React Router 7, and Supabase.

Smart Rename

macOS app · AI engineering

An AI-powered macOS app that renames documents by reading their content, built with Tauri, React, TypeScript, Rust, and the Vercel AI SDK.

Code

See some of my code on GitHub:

GitHub

Availability

From May 1, 2026 I will be available for React, Node.js, TypeScript, and AI-based coding work as a contractor, remotely or in Berlin.

Hire me or check out my CV or my GitHub account.