Johannes is a software engineer, entrepreneur and product manager. He co-founded and scaled voiio to profitability as CTO, led engineering at Thermondo through hypergrowth, and contributes to Django, the wider Python ecosystem and the open-source AI ecosystem (MCP, FastMCP, deer-flow). He ranks in the top 0.8% of GitHub users by stars and advises AI-native startups like fizard (YC W21).

Work Experience

2025/09 – Present	Technical & Executive Advisor (contractor), AI startups & scale-ups fizard (YC W21) — AI-native accounting startup; engineering strategy, AI product architecture and general management voiio — CTO-to-advisor transition; ongoing technical and product sparring for the leadership team
2011/09 – Present	Project Consultant (contractor), selection Cognition AI — eval & benchmarking of Devin Deutsche Telekom — new operating system Momox — senior tech recruiting Rentrop Group — customer acquisition tool IG BCE — software tender advisory +10 more …
2019/06 – 2025/08	Co-Founder & CTO, voiio built the engineering, product and data functions from seed to high profitability; grew the team from 0 to 50 people designed and shipped voiio's first AI employee, Sam, an autonomous Slack agent that handled internal requests end-to-end led platform architecture, security and hiring; shaped product-market fit and recurring revenue model won the NEW WORK Award 2021 (1st place, 200+ entries) and was named Top Start-up Employer (Business Punk & Statista, 2022)
2018/12 – 2019/06	Senior Venture Developer, Thermondo (exit) restructured the customer-service organization and rebuilt core fulfillment workflows to cut Call-Back Cost by 90%
2014/05 – 2018/12	Team Lead Software Engineering, Thermondo (exit) wrote the first lines of code and built the engineering organization through Thermondo's hypergrowth led a team of teams across Android, Backend and Frontend; drove architecture, delivery and hiring scaled the company from 20 to 800 people, with engineering growing from a single team to multiple squads 1st Bloomberg New Energy Pioneer Award (2017), 5th/7th fastest-growing startup in Germany (2015/16, E&Y); 2nd among Europe's Fastest-Growing Companies (FT, 2018)
2012/03 – 2015/10	Co-Founder & Managing Partner, Veerkant (liquidated) led the company from zero to break even
2009/08 – 2011/09	Working Student, Hasso Plattner Ventures

Education

2013/04 – present	Guest Lecturer, Speaker, and Coach d.school — 12-week design thinking program HPI — guest lecture by invitation of Prof. Dr. Werner Zorn
2008 – 2013	IT-Systems Engineering, Hasso Plattner Institut, University of Potsdam
2011 – 2012	Advanced Design Thinking, VNR AG, HPI d.school
2012	Design Challenge: Entrepreneurship, d.school, Stanford University
2011	Basic Design Thinking, Breuninger Stiftung, HPI d.school

Johannes is an ambitious, analytic, and at the same time a creative person who's able to reliably execute time-critical tasks and manage complex situations.
He is a valuable asset to any high power team.

Johannes joined Thermondo even thought he could have picked from a variety of companies - but he chose a business that is aligned with his ideas and that he finds worthy to work for. This decision has always accompanied him during our shared time at Thermondo and made him not only work hard and deliver on his job, but also go beyond and invest in the social ecosystem of the tech team and the whole company. Thank you!

Johannes brought an inspiring combination of deep passion for product development, remarkable technical genius, and genuine people leadership to voiio. He didn't just build; he innovated with a clarity that cut through complexity, always grounded by sharp business street smarts. More importantly, he led with a supportive spirit that empowered our team. His impact was unmeasurable.

Es ist immer gut, wenn man weiß, dass man sich auf bestimmte Leute verlassen kann.

Johannes was an extremely valuable and pleasant team member. He is highly skilled and quickly familiarizes himself with new IT technologies.
He was very committed to the project, solved urgent and important issues without the need for supervision and willingly took on new responsibilities.

Want to chat? Let's grab a coffee together!