Maciej Rząsa
Senior Backend Engineer at Chattermill
Subcarpathian Voivodeship, Poland
Summary
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Rockstar🎓
Top SchoolMaciej Rząsa is a Senior Backend Engineer with 13 years of experience building and scaling Ruby-based systems and developer tooling from Poland's Subcarpathian region. He has led large-scale service extractions, CI improvements and developer experience projects for organisations of hundreds of engineers, and reduced local integration setup time ~4x while at Toptal. An active contributor to the Ruby core — notably improving bigdecimal, optparse and regex/UTF handling — he combines deep runtime-level knowledge with practical engineering trade-offs. He teaches agile and Ruby practices at the university level, mentors growing teams, and has a track record of optimizing monolithic builds, GraphQL migrations, and production CI pipelines. Notably, he blends hands-on systems work (Docker, PostgreSQL/AlloyDB analysis, Jenkins automation) with team facilitation as a Scrum Master, making complex migrations and observability initiatives repeatable and low-friction.
13 years of coding experience
11 years of employment as a software developer
IV Liceum Ogólnokształcące w RzeszowieMSc, Computer Science, MSc, Computer Science at Akademia Górniczo-Hutnicza im. Stanisława Staszica w KrakowieUPC Universitat Politècnica de Catalunya
Polish, English, Spanish, German, Italian
Stackoverflow
23,165reputation
1.2mreached
563answers
65questions
caching
top-5%
activerecord
top-5%
regex
top-5%
rspec
top-5%
ruby
top-1%
ruby-on-rails
top-1%
Github Skills (18)
bigdecimal10
ruby10
ruby-on-rails10
caching9
regex9
rspec9
lang9
activerecord9
regular-expression8
testing8
floating-point6
python6
java6
javascript6
postgresql6
Programming languages (11)
Github contributions (5)
ruby/ruby
Oct 2019 - Feb 2025
The Ruby Programming Language
Role in this project:
Back-end Developer
Back-end DeveloperContributions:2 PRs in 5 years 4 months
Contributions summary:Maciej primarily contributed to the Ruby programming language core, specifically the `bigdecimal` and `optparse` libraries. Their work involved bug fixes, documentation improvements, and enhancing test coverage. They also addressed an issue related to regular expressions and UTF character handling. These commits demonstrate a focus on improving the reliability and functionality of core Ruby libraries.
object-orientedruby-languageprogramming-languagerubyc
regex-performance/regex-performance.github.io
Feb 2018 - Mar 2025
Demo site
Contributions:43 pushes, 1 branch in 7 years 1 month
demo-site
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