Jan Berdajs
Co-Founder at Ethereum and Sons, Jan Berdajs s.p.
Ljubljana, Slovenia
Summary
🤩
Rockstar🎓
Top SchoolJan Berdajs is a co-founder and seasoned software engineer with 14 years of experience building backend systems, cryptocurrency tooling, and consulting on blockchain and Solidity projects from Ljubljana. He blends deep systems-level C and mining experience (sgminer) with modern backend stacks like Ruby on Rails and JavaScript, contributing bug fixes and internationalization and concurrency improvements to notable open-source projects such as Spree and VCR. As founder of the Blockchain Association and an independent cryptocurrency consultant, he pairs product-level thinking with hands-on development and protocol awareness. His work shows a pattern of improving robustness and correctness—thread-safety, lifecycle hooks, and locale handling—highlighting a pragmatic focus on maintainability in production systems.
15 years of coding experience
13 years of employment as a software developer
Bachelor of Science (BSc), Computer Science, Bachelor of Science (BSc), Computer Science at Univerza v LjubljaniGimnazijski maturant, General Studies, Gimnazijski maturant, General Studies at Gimnazija Bežigrad
Github Skills (24)
ecommerce10
thread-safety10
fibers10
testing10
rails10
ruby10
fiber10
spree10
ruby-on-rails10
concurrency10
spreed10
api-design9
calculator9
apim9
calc9
Programming languages (16)
Github contributions (5)
vcr/vcr
Oct 2015 - Jan 2016
Record your test suite's HTTP interactions and replay them during future test runs for fast, deterministic, accurate tests.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:10 commits, 4 PRs, 31 comments in 2 months
Contributions summary:Jan primarily focused on improving the thread safety and overall robustness of the VCR library. They addressed concurrency issues by introducing mutexes and context management within the code. Their contributions included bug fixes, such as correcting Zlib use for JRuby and resolving Webmock thread safety. They also worked on improving fiber handling in around_http_request hooks and preventing the ejection of cassettes by child threads.
spree/spree
Mar 2022 - May 2022
Open Source eCommerce Platform for B2B, Marketplace, and Enterprise. REST API, TypeScript SDK, and production-ready Next.js storefront. Self-host it. Own your stack. No vendor lock-in. Zero platform fees.
Role in this project:Back-end Developer
Back-end DeveloperContributions:5 reviews, 5 commits, 14 PRs in 2 months
Contributions summary:Jan primarily contributed to the Spree eCommerce platform by addressing bugs and improving the codebase. They fixed issues related to SEO URLs, tax rate display, and the handling of calculator subclasses. The user also refactored code to correct lifecycle hooks and enhance internationalization support by fixing issues related to locales with dashes. Their work demonstrates a focus on maintainability, correctness, and internationalization within the Ruby on Rails framework.
ecommercenextjsrestrest-apitypescript
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