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 12 years of experience building and scaling Ruby-centric backends, currently at Chattermill and previously a Principal Engineer at Toptal. He specializes in extracting services from large monoliths (led a GraphQL API extraction serving 200–300 rpm), improving developer experience (reduced local integration setup time ~4x) and designing resilient systems with Ruby/JRuby, GraphQL, MongoDB, Elasticsearch, RabbitMQ and Docker. An active contributor to the ruby/ruby core—having improved bigdecimal, optparse and UTF-aware regex handling—he brings language-level expertise that strengthens reliability across stacks. He also teaches Agile, BDD and practical Ruby at Politechnika Rzeszowska and has a track record of hiring, mentoring and growing high-performing Ruby teams.
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%
ruby-on-rails-5
top-5%
activerecord
top-5%
regex
top-5%
rspec
top-5%
ruby
top-1%
Github Skills (20)
bigdecimal10
ruby10
ruby-on-rails10
ruby-on-rails-59
caching9
regex9
rspec9
lang9
activerecord9
regular-expression8
regular-expressions8
testing8
floating-point6
python6
java6
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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