Marin Petrunić
Protocol Alchemist at Sprinter
Zagreb, Croatia
Summary
🤩
Rockstar🎓
Top SchoolMarin Petrunić is a protocol-focused engineering leader with 11 years of experience building blockchain infrastructure, developer tooling, and production-grade services from Zagreb, Croatia. As former Head of Engineering at ChainSafe and now Protocol Alchemist at Sprinter, he blends hands-on backend engineering in TypeScript/Go/Solidity with people leadership and product-facing delivery. His open-source contributions include deep work on widely used projects like web3.js, libp2p, and a TypeScript Ethereum consensus client (lodestar), where he fixed memory leaks, networking edge cases, and consensus validators—efforts that improve reliability for large decentralized networks. He has co-founded and led R&D teams at NodeFactory and startups, shipping smart contracts, dapps and platform integrations, and even improved developer UX by integrating Swagger UI for beacon APIs. Comfortable moving between low-level protocol fixes and developer ergonomics, Marin pairs pragmatic refactors (CI/bundle checks, ESLint adoption) with a focus on long-term maintainability.
11 years of coding experience
10 years of employment as a software developer
High School Mathematical Gimnasium, High School Mathematical Gimnasium at Gimnazija KarlovacBachelor’s Degree Software Engineering and Information System, Bachelor’s Degree Software Engineering and Information System at Faculty of Electrical Engineering and Computing, Zagreb
English, German, Croatian
Stackoverflow
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Github Skills (37)
puppeteer10
javascript10
apidoc10
netstack10
net10
typescript10
ui-design10
networking10
libp2p10
abi10
go10
swagger-ui10
api10
web3js10
ethereum10
Programming languages (19)
Github contributions (5)
ethereum/beacon-APIs
Oct 2019 - Dec 2022
Collection of RESTful APIs provided by Ethereum Beacon nodes
Role in this project:
Front-end Developer
Front-end DeveloperContributions:133 reviews, 353 commits, 125 PRs in 3 years 2 months
Contributions summary:Marin primarily focused on enhancing the user interface of the Ethereum Beacon APIs documentation. They integrated Swagger UI to provide interactive API documentation, improving the user experience. This involved adding and updating the Swagger UI version and making cosmetic improvements, such as adding an Ethereum logo and adjusting the display of request durations. The user also configured the UI for easier navigation and version selection.
apiredocethereumspecificationrestful
ChainSafe/dappeteer
Feb 2021 - Jan 2023
[DEPRECATED]🏌🏼E2E testing for dApps using Puppeteer + MetaMask
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:125 reviews, 80 commits, 96 PRs in 1 year 11 months
Contributions summary:Marin primarily contributed to dependency updates and refactoring within the codebase. Their work focused on bumping project dependencies, specifically related to the core functionality of the dappeteer library, likely to enhance functionality or address vulnerabilities. They also added and configured ESLint, contributing to code quality and maintainability. These changes suggest a developer working on the project's core features and maintaining its health.
pupeteerdappethereumdappspuppeteer
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