Marcel De Graaf
CTO & Co-founder at Walter Living
Gelderland, Netherlands
Summary
👤
Senior🎓
Top SchoolMarcel De Graaf is a CTO and co-founder with 15 years of experience building scalable, user-friendly software and cloud infrastructure from Dutch startups to enterprise clients. He leads product and engineering at Walter Living, helping everyday people make better home buying and selling decisions, while drawing on prior co‑founder experience delivering high‑tech prototypes and secure healthcare and financial systems at Beta Corp. Marcel’s background spans full-stack development and operations—designing AWS infrastructures that served hundreds of thousands of users and transitioning teams from product to production-ready services. He contributes to open-source tooling in the Ruby ecosystem, having maintained and refactored a Google Places API wrapper with thorough testing and bug fixes. Comfortable toggling between hands-on engineering and strategic leadership, he prioritizes pragmatic, maintainable solutions that balance security, privacy, and usability. Based in Gelderland, he combines startup grit with a track record of dependable systems for clients like ABN‑Amro and Ericsson.
15 years of coding experience
10 years of employment as a software developer
Information Technology, Information Technology at Fontys University of Applied SciencesHigh School, Sciences and Mathemathics, High School, Sciences and Mathemathics at Sint Pietersinstituut Turnhout
Stackoverflow
51reputation
3kreached
0answers
2questions
Github Skills (9)
rspec10
google-places-api10
ruby10
httparty9
emberjs6
kubernetes6
istio6
google-kubernetes-engine6
highcharts6
Programming languages (15)
Github contributions (5)
qpowell/google_places
May 2011 - May 2015
A Ruby wrapper around the Google Places API
Role in this project:
Back-end Developer
Back-end DeveloperContributions:123 commits, 4 PRs, 9 pushes in 4 years
Contributions summary:Marcel primarily contributed to the implementation and maintenance of the `google_places` Ruby wrapper. Their work involved defining classes, methods, and attributes to interact with the Google Places API. They also wrote unit tests to ensure the functionality and accuracy of the code. Furthermore, the user refactored the code and fixed errors to improve code quality and address API inconsistencies.
ruby-wrapperapigoogle-apigoogleruby
marceldegraaf/sethdegraaf.nl
Nov 2018 - Apr 2025
Contributions:8 pushes, 1 branch in 6 years 5 months
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