Tomasz Krzyżowski
Senior Product Engineer at Attio
Lower Silesian Voivodeship, Poland
Summary
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Rockstar🎓
Top SchoolTomasz Krzyżowski is a Senior Product Engineer with a decade of experience building React and React Native applications, now shaping product engineering at Attio after senior roles at Nearform and Callstack. A functional-programming and algorithmics enthusiast, he blends pragmatic full‑stack skills with a strong interest in data science and performance engineering. Tomasz is an active open-source contributor (notably to Callstack's repack and reassure projects), improving mobile build tooling, asset handling and performance testing workflows. He has a track record of shipping cross-platform optimizations and instrumenting Jest-based performance tests, reflecting a focus on measurable user and developer experience improvements. Based in Lower Silesia, Poland, he pairs continual self-development with hands-on delivery in fast-moving teams.
10 years of coding experience
7 years of employment as a software developer
Inżynier (Inż.) Informatyka, Inżynier (Inż.) Informatyka at Wrocław University of Science and Technology
Stackoverflow
23reputation
665reached
0answers
2questions
Github Skills (25)
javascript10
ios10
performance-monitor10
react-native10
testing10
typescript10
webpack10
performance-testing10
performance-analysis10
jestjs10
android10
webpacker10
typescript-types10
typescripts10
react10
Programming languages (7)
Github contributions (5)
callstack/reassure
Feb 2022 - Mar 2022
Performance testing companion for React and React Native
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:24 commits in 24 days
Contributions summary:Tomasz primarily contributed to the performance testing aspects of the `reassure` repository, a tool designed for performance testing React and React Native applications. Their work involved adding example tests and configurations using Jest for performance measurements. Additionally, they refactored the measure file and built a markdown builder, demonstrating involvement in both test implementation and output formatting. The user also made adjustments to the build process, including eslint configuration, and scripts.
regressionreactreact-nativetestingperformance
callstack/repack
Oct 2021 - Jul 2022
A webpack-based toolkit to build your React Native application with full support of webpack ecosystem.
Role in this project:Mobile Developer
Mobile DeveloperContributions:3 reviews, 13 commits, 8 PRs in 8 months
Contributions summary:Tomasz primarily contributed to the `callstack/repack` repository, which is a webpack-based toolkit for React Native applications. Their commits focused on enhancing the iOS and Android builds. They worked on adding features like chunk request timeouts, handling absolute paths for filesystem chunk loading, and inlining assets to optimize asset loading performance.
reactbundlerreact-nativecode-splittingecosystem
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