Marcin Czarnecki
Engineering Manager at Box
Warsaw, Masovian Voivodeship, Poland
Summary
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RockstarMarcin Czarnecki is an engineering manager based in Warsaw with 11 years of experience leading backend teams and shaping technical roadmaps at companies like Box, Westwing, and GOG. He combines hands-on PHP and backend engineering expertise—demonstrated by contributions to a popular serializer library—with people leadership, mentoring, and operational responsibilities across multiple squads. At GOG he progressed from PHP developer to chapter lead and tech lead, driving sustainable architectures, performance improvements, and measurable development KPIs. More recently he led a six-person marketing tech team and now manages engineering at Box, blending delivery focus with stakeholder collaboration. Colleagues describe him as a pragmatic technologist who balances code-level improvements with long-term vision and developer enablement.
10 years of coding experience
9 years of employment as a software developer
Github Skills (11)
deserialization10
php10
data-serialization10
serialization10
annotate9
annotations9
annotation-processing9
unit-testing9
json8
xml8
performance-optimization7
Programming languages (3)
Github contributions (5)
schmittjoh/serializer
Jul 2018 - Apr 2022
Library for (de-)serializing data of any complexity (supports JSON, and XML)
Role in this project:
Back-end Developer
Back-end DeveloperContributions:8 releases, 94 reviews, 27 commits in 3 years 9 months
Contributions summary:Marcin primarily contributed to implementing and improving the serialization and deserialization features of the `serializer` library. They focused on adding support for inline deserialization, updating documentation, and enhancing the handling of iterators and generators. The contributions included code style fixes, test improvements, and the introduction of a new iterator handler. The user also worked on improving the performance of max depth exclusions.
serializingcomplexityxmlserializationserializing-data
scyzoryck/serializer
Jul 2018 - Apr 2025
Library for (de-)serializing data of any complexity (supports XML, JSON, YAML)
Contributions:114 pushes, 57 branches in 6 years 10 months
yamlserializingcomplexityxmlserialization
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