Karol Słuszniak
CTO at Rey
Warsaw, Masovian Voivodeship, Poland
Summary
👤
Senior🎓
Top SchoolKarol Słuszniak is a pragmatic CTO and founder with 11+ years of experience building and scaling web products from the ground up, combining hands-on Ruby on Rails, Elixir/Phoenix and React expertise with product-minded technical leadership. He led major architecture and growth efforts at Fresha/Shedul—helping the product scale from a small team to a global SaaS with a $105M valuation—and now runs multiple ventures including Heyplay.io and Pubray while serving as Rey’s CTO. Karol is equally at home shipping backend architecture and crafting playful multiplayer browser games, reflecting a rare blend of infrastructure rigor and product-driven creativity. An active tech blogger and longtime open-web enthusiast, he often experiments with DevOps automation and game mechanics to make technology more approachable. Based in Warsaw, he brings entrepreneurial grit, a track record of introducing Elixir/Phoenix into Rails teams, and an appetite for turning ambitious ideas into polished, user-facing systems.
11 years of coding experience
11 years of employment as a software developer
Master's degree, Computer Science, Master's degree, Computer Science at AGH University of Krakow
English, Polish
Stackoverflow
501reputation
29kreached
1answer
0questions
Github Skills (105)
realtime10
sms10
e-mail10
code-analysis10
rigid-bodies10
command-line-tool10
javascript10
bounce10
phone-number10
continuous-integration10
elixir10
physics10
api-server10
phoenix-framework10
actionmailer10
Programming languages (7)
Github contributions (5)
visualitypl/textris
Dec 2014 - Aug 2016
Implement texter classes for sending SMS messages in similar way to how e-mails are sent with ActionMailer-based mailers. Take advantage of e-mail proxying and enhanced phone number parsing, among others.
Contributions:83 commits, 4 PRs, 18 pushes in 1 year 8 months
sms-messagessendingbounceactivemodelsimilar
surgeventures/click-monorepo
Nov 2017 - Nov 2017
Contributions:51 commits, 55 pushes, 2 branches in 8 days
monorepoend-to-endcontinuousdockermicroservices
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