I've been a software developer and engineering leader for over two decades, blending deep technical expertise with a passion for AI innovation. I thrive on building strong engineering cultures, delivering high-impact products, and mentoring teams to achieve excellence. I remain actively engaged in the developer community as the proud maintainer of the open source Reek gem. I’ve spent most of my professional life in international startups with a strong focus on engineering culture and productivity, and I excel at building the right teams and scaling them up as the business grows.…

Timo Roessner

I've been a software developer and engineering leader for over two decades, blending deep technical expertise with a passion for AI innovation. I thrive on building strong engineering cultures, delivering high-impact products, and mentoring teams to achieve excellence. I remain actively engaged in the developer community as the proud maintainer of the open source Reek gem. I’ve spent most of my professional life in international startups with a strong focus on engineering culture and productivity, and I excel at building the right teams and scaling them up as the business grows.…

Available to hire

I’ve been a software developer and engineering leader for over two decades, blending deep technical expertise with a passion for AI innovation. I thrive on building strong engineering cultures, delivering high-impact products, and mentoring teams to achieve excellence.

I remain actively engaged in the developer community as the proud maintainer of the open source Reek gem. I’ve spent most of my professional life in international startups with a strong focus on engineering culture and productivity, and I excel at building the right teams and scaling them up as the business grows.

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Skills

Experience Level

Python
Expert
Data Visualization
Expert
Docker
Expert
Ruby
Expert
SQL
Expert
JavaScript
Intermediate
Kubernetes
Intermediate
TypeScript
Intermediate
GitHub CoPilot
Intermediate

Language

German
Fluent
English
Fluent

Work Experience

Fractional CTO / Freelance Developer at Toptal
March 1, 2020 - December 1, 2022
Managed product-related development teams (around 150 developers, 25 teams).
Director of Engineering at TopTal
October 1, 2018 - March 1, 2021
Led engineering teams and built new analytics products on top of large data assets.
Director of Platform Engineering at Planet
October 1, 2016 - December 1, 2017
Led a team of sustainability experts; supported food manufacturers, agricultural traders, financial institutions, NGOs and government agencies to understand land conversion risks and reduction opportunities using Python and Google Cloud.
CTO at Adastra
January 1, 2023 - April 1, 2025
Interim CTO-level leadership; drove AI strategy, coaching, technical vision and rapid AI feature development; led teams building AI-powered solutions.
Fractional CTO at Turf Coach
May 1, 2025 - Present
Sports tech startup delivering real-time data analytics on football pitch conditions; combined AI, sensors and software to deliver insights; led AI strategy and scaling the engineering organization.

Education

Bachelor of Science in Bioinformatics at Freie Universität Berlin
January 1, 2002 - January 1, 2005

Qualifications

Add your qualifications or awards here.

Industry Experience

Software & Internet, Professional Services, Media & Entertainment, Education, Gaming
    Reek Code Smell Detector (more than 30 million downloads)

    Reek is a tool that examines Ruby classes, modules and methods and reports any Code Smells it finds.

    https://www.twine.net/signin