Dennis Felsing
Software Engineer In Test at Materialize
Heidelberg, Baden-Württemberg, Germany
Summary
🤩
Rockstar🎓
Top SchoolDennis Felsing is a Software Engineer in Test with 17 years of experience building robust testing and developer tooling for databases and systems software. Currently at Materialize after driving fuzz testing, automated coverage, and Postgres-compatible test infrastructure at Yugabyte, he has a track record of finding hundreds of subtle crash and correctness bugs. Previously at SAP HANA he introduced Python-based code quality tooling and randomized SQL testing that uncovered extensive engine issues, and he mentors engineers while improving developer experience. An active open-source contributor, Dennis has also shaped core game engines and the Nim language libraries—fixing platform RNGs, adding algorithmic utilities, and implementing a Lisp interpreter—showing deep systems-level expertise across C++, Nim, and Python. Based in Heidelberg, he blends rigorous academic foundations from KIT with pragmatic, reproducible testing techniques that catch the bugs others miss.
17 years of coding experience
7 years of employment as a software developer
High School, Information Technology, High School, Information Technology at Technical High School BrettenMaster’s Degree, Computer Science, Master’s Degree, Computer Science at Karlsruher Institut für Technologie (KIT)
English, German
Github Skills (44)
algorithm10
nim-lang10
algorithms10
programming-language10
c-language10
postgresql10
gameplay10
distributed-systems10
c1110
database-testing10
data-structure10
videogames10
c1710
sql10
data-structures10
Programming languages (29)
Github contributions (5)
ddnet/ddnet
Jul 2015 - Jan 2023
DDraceNetwork, a free cooperative platformer game
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1996 reviews, 848 commits, 3117 PRs in 7 years 8 months
Contributions summary:Dennis primarily worked on addressing compiler warnings related to clang-tidy, improving code readability, and correcting typographical errors within the source code. Their work focused on various aspects of the game, including fixing issues in character behavior, server-side game logic, and the user interface. Additionally, they implemented a feature related to team management and corrected documentation issues.
2d-gameteeworldsgamewindowsplatformer
nim-lang/Nim
Jun 2014 - Feb 2018
Nim is a statically typed compiled systems programming language. It combines successful concepts from mature languages like Python, Ada and Modula. Its design focuses on efficiency, expressiveness, and elegance (in that order of priority).
Role in this project:Back-end Developer
Back-end DeveloperContributions:335 commits, 150 PRs, 18 pushes in 3 years 8 months
Contributions summary:Dennis primarily contributed to the Nim programming language's core libraries by implementing and improving various functionalities. Their work includes the addition of procedures and templates within the `sequtils` and `algorithm` modules, such as `keepIf`, `keepIfIt`, `reversed`, and `sortByIt`. They also added and updated various mathematical and system procedures related to unsigned integers, complex numbers, and file system objects. Additionally, they fixed a bug in the http client module and added some support for the Nimrod command line.
pythonnim-langelegancecompilerprogramming-language
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