Work I do

From AI-native product development to open source and community building — here is a selection of projects I have built and contributed to.

Companies I worked with

Over 15 years with startups and enterprise — Joyn / ProSiebenSat.1, Fiberfone, AXA, REWE digital, Vaillant Group, and more.

My own projects

N+One

AI-native coaching platform for cyclists. Chat-first Dynamic Coach that turns training and recovery data into the next session decision — with integrations for Garmin, Strava, Whoop, and intervals.icu.

Founder, since April 2026

Fiberfone GmbH

Fractional CTO leading technical strategy and a 23M+ data point infrastructure for automated location-based order management. Architected agentic AI systems and low-code crawling processes.

Fractional CTO, October 2023 – February 2026

Digitale Leute School

Coach for AI Software Engineering and Vibe Coding bootcamps — production AI patterns including resilient RAG pipelines, MCP integrations, vector stores, guardrails, and spec-driven agentic workflows with OpenSpec and Cursor.

Coach, since June 2026

Warhol

Warholautomates UI and web design testing with laser focus on speed, efficiency, and developer productivity. Warhol's algorithms turn your existing pattern library into tests that can verify component implementation and design consistency on your production web interface.

Together with Peter Kröner I worked on this tool and we love to make web development more easy.

Co-founder, January 2019 – July 2021

Community and Open Source

Working Draft

Working Draft is a wildly recognized German weekly news podcast for web developers. I am a co-hosts of the show.

Find out more about the Working Draft in the Podcasting section

Co-host since 2012, podcast exists since 2011

NightlyBuild

NightlyBuild is a hand-crafted after work conference for web enthusiasts loving technology, design and inspiration in Cologne, Germany.

Together with four colleagues we created the friday-evening conference for four years and had a blast in working with speakers from around the world as well as locals.

First conference done in 2014 - 2018

HTML5 Boilerplate

I am a member of the HTML5 Boilerplate developer’s team. It is the web’s most popular front-end template.

Part of development team 2012 - 2014

CSS Modal

CSS Modal is a modal overlay which can be used without JavaScript as a requirement. It is Open Source.

Development since 2013

Selected client work

Joyn / ProSiebenSat.1

As Vice President Engineering I owned the customer-facing applications of the multi-tenant streaming platform Joyn (11M+ MAU). Led six distributed teams (~55 people), reference architectures, budget, and the Joyn / ProSiebenSat.1 merger transformation — including early AI engineering practices.

Vice President Engineering, October 2021 – June 2025

FYEO at ProSiebenSat.1

As Director of Technology & Product I led FYEO, a podcasting app with over 1.6 million formats and 40 million episodes. Built an internal team of 13, replaced an external agency, and aligned product and engineering roadmap with business owners.

Director Technology & Product, July 2020 – September 2021

AXA Deutschland

Led engineering for online insurance tariff calculators in a strongly regulated environment. Node.js and Java microservices, React / TypeScript frontends, Kubernetes and Docker — raising annual application delivery from 2 to 6 and growing the team from 4 to 14.

Lead Software Engineer & Architect, July 2018 – September 2019

REWE digital

Built Node.js microservices moving backend workloads from on-premise to Google Cloud Platform with Kubernetes and Docker. Introduced Apache Kafka for streaming and a React micro-frontend architecture.

Software Engineer, July 2017 – June 2018

Vaillant Group

Front-end architect for Vaillant Group and subsidiaries — shaping a scalable, reusable front-end environment and pioneering agile transformation while the organisation grew from seven to about 40 people in Scrum.

Front-end Architect, October 2013 – January 2015

Croozer GmbH

Croozer produces and sells trailers for all types of bicycles to transport your kids, dogs or cargo.
I prepared the relaunch of their Magento-based web-shop and underlying architecture to a micro services oriented architecture.

Year of development: 2017

Fashionette

Founded in 2009, Fashionette is a e-commerce company selling luxury and premium handbags and small leather goods.
Together with the team at Fashionette I prepared the relaunch of their Magento-based web-shop and underlying architecture. I was responsible to develop the architecture and guide the team in developing it. Furthermore I re-introduced Scrum and was responsible for scaling from one Scrum team to two including freelancers and remote workers.

Year of development: 2016

Siteeffect

Siteeffect is a startup developing a visual regression testing tool for developers and product managers helping with quality assurance. As a front-end developer for their web app I developed the visual interface with React.js.

Year of development: 2015

Share A Camper

If you ever want to travel through New Zealand with a campervan check out Share A Camper. They realize private campervan hiring. I initally set up the architecture of the front-end with the team.