Maciej Krajowski
CTO at platformOS
Warsaw, Masovian Voivodeship, Poland
Summary
👤
Senior🎓
Top SchoolMaciej Krajowski is a pragmatic CTO and seasoned full‑stack engineer with 13 years of experience building scalable web platforms, currently leading platformOS from Warsaw. He specializes in backend systems and developer productivity, championing test-driven practices and having driven practical process improvements (introducing staging, tests and Git) across several teams. His career spans building peer-to-peer marketplace platforms and high‑availability Rails systems, with hands-on experience across Ruby on Rails, Grails, PHP and modern CI workflows. Known for turning complex product requirements into maintainable, extensible code, he balances technical leadership with day‑to‑day engineering. Outside work he’s unusually social for an engineer—an avid dancer and multisport competitor—bringing team energy and discipline to engineering culture.
13 years of coding experience
10 years of employment as a software developer
MSc, Computer Science, MSc, Computer Science at Danmarks Tekniske Universitet / DTUBS, Computer Science: Software Engineering, BS, Computer Science: Software Engineering at Wyższa Szkoła Informatyki Stosowanej i Zarządzania WIT w Warszawie
English, Polish, German
Github Skills (34)
bootstrap-select10
documentation10
raygun9
activemodel9
elastic8
cli8
sinatra8
marketplace8
form-objects8
rails8
error-handling8
error-reporting8
ruby-on-rails7
elasticsearch6
nodejs6
Programming languages (9)
Github contributions (5)
Platform-OS/pos-module-core
Feb 2023 - Jan 2026
Contributions:32 reviews, 22 PRs, 47 pushes in 2 years 11 months
Platform-OS/pos-module-data-export-api
Mar 2024 - Jul 2025
Contributions:1 review, 1 PR, 11 pushes in 1 year 3 months
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