Marvin Hagemeister
Software Engineer at Deno
Wuppertal, North Rhine-Westphalia, Germany
Summary
🤩
RockstarMarvin Hagemeister is a Senior Staff Software Engineer with 11 years of experience building fast, pragmatic web tooling and developer-focused libraries. He blends front-end craft with build tooling and runtime work—contributing to notable open-source projects like Preact, microbundle, redux-persist and the Deno standard library—often improving bundling, compatibility, and core signal/state logic. Having held senior roles at Shopify and Deno, he repeatedly tackles build configuration, performance and developer experience problems at scale. Marvin favors simplicity and speed in both code and developer workflows, and has a track record of reducing bundle sizes, fixing subtle compatibility issues, and adding robust test coverage. Based in Wuppertal, Germany, he brings a practical, full-stack mindset that surfaces in contributions ranging from CSS and CLI UX fixes to core reactive primitives.
11 years of coding experience
4 years of employment as a software developer
Stackoverflow
3,001reputation
355kreached
41answers
4questions
sorting
top-5%
javascript
top-5%
typescript
top-5%
Github Skills (57)
babel610
deno10
javascript10
routers10
testing10
css10
router10
typescript10
responsiveness10
reactivity10
ui-design10
signal10
redux10
webpack10
uid10
Programming languages (28)
Github contributions (5)
preactjs/wmr
May 2020 - Mar 2022
👩🚀 The tiny all-in-one development tool for modern web apps.
Role in this project:
Front-end Developer
Front-end DeveloperContributions:54 releases, 229 reviews, 1001 commits in 1 year 10 months
Contributions summary:Marvin primarily contributed to the development of the Preact-based WMR development tool. They worked on bug fixes, including correcting character encoding warnings and fixing issues in CSS module hot module reloading. Their work encompassed adding support for features like import assertions and class fields. They were also responsible for incorporating a number of design enhancements, including the addition of a theme switcher.
rollupreactall-in-onetinyjavascript
preactjs/signals
Aug 2022 - Oct 2022
Manage state with style in every framework
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:15 releases, 116 reviews, 276 commits in 2 months
Contributions summary:Marvin primarily contributed to the core logic and functionality of the Preact signals library. Their work included implementing the core signal and computed functionalities, adding support for subscriptions, and introducing features like batching and error handling. They also made updates to the test suite, implemented fixes, and refactored components to improve the library's overall performance and reliability, demonstrating a strong focus on the project's internal workings.
reactstate-managementreactivitypreactredux
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