Jan Stępień
Senior Consultant at INNOQ
Berlin, Germany
Summary
👤
Senior🎓
Top SchoolJan Stępień is a Senior Consultant based in Berlin with 18 years of software engineering experience, helping organisations design and deliver reliable, scalable, and maintainable systems at INNOQ. He combines hands-on implementation—evident from core contributions to projects like the high-performance Topaz Ruby interpreter and performance optimizations in the Code Maat analysis tool—with coaching and mentoring to shorten feedback loops and simplify complex designs. An advocate for prototyping and validating hypotheses, he blends practical engineering with facilitation skills to empower teams and team leads. Jan holds MSc and BSc degrees summa cum laude in Computer Science from Politechnika Warszawska and studied hypermedia at the University of Tampere, reflecting a strong academic foundation. Outside client work he shares knowledge through writing and speaking, and his GitHub tagline, "Bringing balance to parentheses," hints at a pragmatic attention to both correctness and elegance.
18 years of coding experience
5 years of employment as a software developer
Computer Science, Hypermedia, Computer Science, Hypermedia at University of TampereWarsaw University of Technology
English, German, Polish
Github Skills (11)
clojure10
code-optimization10
parallel-processing10
interpreter10
clojure-cli10
ruby10
testing9
transducer9
strings8
process-management8
text-manipulation8
Programming languages (11)
Github contributions (5)
topazproject/topaz
Feb 2013 - Jul 2013
A high performance ruby, written in RPython
Role in this project:
Back-end Developer
Back-end DeveloperContributions:132 commits, 2 PRs in 5 months
Contributions summary:Jan primarily contributed to the core functionality of the Ruby interpreter "topaz". Their work involved implementing and refactoring Ruby language features like `Enumerable#reduce`, `Array#+`, `String#insert`, and `Hash#{merge,merge!}`. The user also worked on implementing the `Process` module methods, improving the system's support of the Ruby language's standard library. Furthermore, they modified and added tests to verify the correct behavior of their changes.
performancepythonrubyhigh-performance
adamtornhill/code-maat
Aug 2015 - Aug 2015
A command line tool to mine and analyze data from version-control systems
Role in this project:Back-end Developer
Back-end DeveloperContributions:5 commits, 1 PR, 3 comments in 1 day
Contributions summary:Jan focused on optimizing the performance of the hiccup-based parser within the `code-maat` tool. They implemented parallel processing using `pmap` and `reducers/fold` to speed up parsing. Furthermore, they refactored the `as-entry-tokens` function to use transducers and simplified entry line generation, contributing to a more efficient parsing process. These changes resulted in noticeable performance improvements when analyzing larger codebases.
command-line-toolversion-controlanalyze-datarefactoringcode-analysis
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