Bartosz Kalinowski
Chief Technology Officer (CTO) at Walnut
Warsaw, Masovian Voivodeship, Poland
Summary
👤
Senior🎓
Top SchoolBartosz Kalinowski is a pragmatic technology leader and Elixir enthusiast with 11 years of experience building backend systems, payment gateways, and commercial web apps. As CTO of Melina Krzemowa and senior engineer at companies like BlockFi and Walnut, he blends hands-on development in Elixir/Phoenix with full-stack experience in React and occasional forays into ReScript. He has shipped financial and gaming systems—implementing Bitcoin integrations, CFD/Binary Options engines, and casino game math—demonstrating a strong grounding in reliable, high-throughput services. Known for quickly adopting new technologies and preferring the elegance of functional approaches when appropriate, he also brings hardware and maker sensibilities from 3D printing, electronics, and game projects. Based in Warsaw, he combines optimism and curiosity with practical delivery, often translating niche technical experiments into commercial features.
11 years of coding experience
9 years of employment as a software developer
Computer Science, Computer Science at Polish-Japanese Academy of Information Technologydropped for IT Mathematics, dropped for IT Mathematics at Warsaw University of Technology
English, Japanese, German
Stackoverflow
2,522reputation
180kreached
66answers
42questions
Github Skills (200)
bitcoind10
programming-language10
ecto10
scalable10
elixir10
embedded-ruby10
plug10
functional-programming10
rendering9
javascript9
phaser9
vultr9
api9
dart9
compiler9
Programming languages (12)
Github contributions (5)
solatis/gold
Apr 2016 - Aug 2020
Elixir interface to Bitcoin RPC API
Contributions:66 commits, 14 PRs, 13 pushes in 4 years 5 months
apirpcrpc-apibitcoin-rpcelixir
kelostrada/depot
Jan 2020 - Feb 2025
Laravel test project to store stocks and products and generate inventarisation datta
Contributions:12 PRs, 54 pushes, 2 branches in 5 years 1 month
test-projectphplaravel-testlaravelstocks
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