Max Kellermann
Principal Software Engineer at Freelance
Cologne Bonn Region Germany
Summary
🤩
Rockstar🎓
Top SchoolMax Kellermann is a Principal Software Engineer with 26 years of hands-on experience designing and optimizing backend and infrastructure systems in C++, currently writing C++20 at IONOS and freelancing since 1999. A self-taught programmer since childhood, he combines deep systems-level expertise with a relentless focus on performance, memory safety, and code quality. His open-source footprint spans high-profile projects like Ceph, Kodi, Zeek, and util-linux, where he has reduced lock contention, fixed critical memory bugs, and improved const-correctness across large codebases. Max regularly undertakes low-level improvements—enabling transparent huge pages, switching to monotonic clocks, and eliminating expensive patterns from hot loops—that yield measurable runtime gains. Based in the Cologne–Bonn region, he pairs a pragmatic engineering mindset with a long history of contributing subtle but high-impact fixes to infrastructure software.
26 years of coding experience
2 years of employment as a software developer
Abitur, Abitur at Otto-Hahn-Gymnasium
Github Skills (55)
socket-io10
debugging10
code-optimization10
debug10
filesystem10
mpd10
c-language10
apcu10
multithreading10
network-analysis10
nfs10
io-uring10
memory-management10
locking10
linux10
Programming languages (17)
Github contributions (5)
MusicPlayerDaemon/MPD
Jun 2008 - Jan 2023
Music Player Daemon
Role in this project:
Back-end Developer
Back-end DeveloperContributions:171 reviews, 11076 commits, 535 PRs in 14 years 9 months
Contributions summary:Max contributed to the MPD (Music Player Daemon) project by addressing various issues, including improving the handling of file URIs, fixing playlist functionality, and upgrading build processes. Their contributions focused on code improvements within the C++ codebase, incorporating library integrations (like libfmt), and addressing memory management issues. They also made improvements to documentation.
audio-playermusic-player-daemonmpd-clientdaemonlinux
zeek/zeek
Jan 2020 - Mar 2020
Zeek is a powerful network analysis framework that is much different from the typical IDS you may know.
Role in this project:Back-end Developer
Back-end DeveloperContributions:182 commits, 28 PRs, 77 comments in 1 month
Contributions summary:Max primarily focused on optimizing the Zeek network analysis framework, contributing code changes focused on performance improvements. Their work involved refactoring and optimizing existing code, such as eliminating sscanf() and realloc() calls from loops and replacing them with more efficient methods. The user also fixed memory leaks in various modules, demonstrating a strong understanding of memory management within the codebase. Their contributions demonstrate a focus on enhancing the efficiency and reliability of the Zeek framework.
dfirnsmsecurityanalysisnetworking
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