Marek Kirejczyk
CTO, Founder at vlayer Labs
Warsaw, Masovian Voivodeship, Poland
Summary
🤩
Rockstar🎓
Top SchoolMarek Kirejczyk is a seasoned technology founder and CTO with 11 years of experience building engineering teams and shipping blockchain and web products from Warsaw. He co-founded vlayer.xyz and zkWarsaw and has a track record of scaling organizations—having led engineering at Archblock, founded ETHWORKS (acquired), and grown teams at Daftcode and EL Passion. A hands-on full-stack developer, Marek contributes to prominent open-source Ethereum tooling (e.g., Waffle and useDApp), improving smart contract testing, network support, and developer experience. He combines deep technical chops across Ruby, smart contracts, and front-end stacks with operator experience in productization and M&A. Notably, he pairs low-level protocol work with developer ergonomics, making complex blockchain tooling easier to adopt.
11 years of coding experience
12 years of employment as a software developer
Erazmus programme, Computer Science, Erazmus programme, Computer Science at Vrije Universiteit Amsterdam (VU Amsterdam)Master, Computer Science, Master, Computer Science at University of Warsaw
English
Stackoverflow
5,404reputation
496kreached
11answers
0questions
generics
top-1%
mockito
top-1%
java
top-5%
algorithm
top-5%
Github Skills (32)
solidity10
ethersjs10
testing10
typescript10
ganache10
daap10
ruby10
chai10
ethereum10
typescript-types10
generics10
smart-contracts10
typescripts10
mockito10
react10
Programming languages (14)
Github contributions (5)
EthWorks/ethereum.rb
Oct 2016 - Mar 2020
Ethereum library for the Ruby language
Role in this project:
Back-end Developer
Back-end DeveloperContributions:10 releases, 199 commits, 52 PRs in 3 years 6 months
Contributions summary:Marek primarily contributed to the core functionality of the Ethereum library for Ruby. Their work involved fixing bugs and improving test coverage within the `client_spec.rb` file. They added features like a contract estimate function, improved deployment and method call functionality, and incorporated logging to enhance debugging capabilities. The user also updated the version number in multiple commits, signaling incremental improvements and bug fixes.
ethereumrubyparitysolidity
TrueFiEng/Waffle
Jul 2018 - Mar 2021
Library for writing and testing smart contracts.
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:43 releases, 87 reviews, 155 commits in 2 years 8 months
Contributions summary:Marek contributed significantly to the project's development by implementing and testing smart contracts, including their structure and compilation process. They were involved in setting up the project structure and testing environment using Chai and Ganache. Furthermore, they refactored the code, adding linting and build processes, enhancing the overall project quality and developer experience. They also added new chai matchers and updated the example.
smart-contractstesting
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