Mark Van Seventer
Senior Software Engineer at Dropbox
Boston, Massachusetts, United States
Summary
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Rockstar🎓
Top SchoolMark Van Seventer is a Senior Software Engineer based in Boston with 15 years of experience building high-performance web applications and media systems. A front-end specialist in React and TypeScript, he pairs deep web-standards and performance focus with full-stack contributions—evident from refactoring the widely used UnCSS project and enhancing core playback and ad integrations for JW Player. He has driven engineering at companies from startups to Dropbox, often improving core logic, tests, and dependency hygiene to keep projects secure and maintainable. Curious about AI and "Vibe Coding," he blends productivity experiments with pragmatic engineering practices. Trained with an MSc from Vrije Universiteit Amsterdam, he brings both academic rigor and hands-on craftsmanship to complex front-end and media challenges.
14 years of coding experience
17 years of employment as a software developer
MSc, MSc at Vrije Universiteit AmsterdamUniversity Preparatory School, University Preparatory School at VeenLanden College
Github Skills (12)
testing10
html10
css10
mplayer10
video-ads10
javascript10
media-player10
player10
jsdom10
postcss9
nodejs9
build-tools7
Programming languages (10)
Github contributions (5)
jwplayer/jwplayer
Jan 2018 - Feb 2020
JW Player is the world's most popular embeddable media player.
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:117 commits, 46 PRs, 81 pushes in 2 years 1 month
Contributions summary:Mark primarily contributed to the JW Player's core functionalities, with a focus on enhancing the codebase by implementing features related to autoplay behavior, media pool management, and outstream ad integrations. They also performed code reviews, optimized concurrent autoplay tests, and updated media pool unit tests. Their work involved modifying both the front-end (UI) and back-end components to ensure compatibility and improve overall player performance, particularly around ad integrations.
html5-videoandroidmedia-playervideo-playermse
uncss/uncss
Dec 2016 - Jul 2017
Remove unused styles from CSS
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:9 commits, 1 PR, 12 comments in 6 months
Contributions summary:Mark refactored and updated the UnCSS codebase, replacing PhantomJS with jsdom for HTML parsing. They made significant changes to the core `uncss.js`, `phantom.js`, and `jsdom.js` files, including modifications to the `getHTML` and `getStylesheets` functions, indicating involvement in the core logic of the project. Furthermore, they updated dependencies, demonstrating a focus on maintaining the project's functionality and addressing potential vulnerabilities, while simultaneously updating the existing tests to match the changed system.
unusedcssjavascriptstylesheetspostcss
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