Mattias Buelens
Senior Staff Engineer at THEO Technologies
Leuven, Flemish Brabant, Belgium
Summary
🤩
Rockstar🎓
Top SchoolMattias Buelens is a Senior Staff Engineer with 13 years of experience building and leading development of THEOplayer, now part of Dolby Laboratories, where he blends deep runtime and web-platform expertise with product-facing media engineering. He has a strong track record in streaming, HTML5 media, and browser APIs, contributing to core projects like Node.js, WHATWG Streams, and the Web Platform Tests—work that demonstrates attention to standards, correctness, and interoperability. As a former lead architect and team lead at THEO, he repeatedly moved between hands-on runtime fixes and high-level design decisions for universal video playback. His open-source contributions span both front-end frameworks (Svelte) and tooling (TypeScript DOM generator), highlighting an ability to improve developer ergonomics around media. Based in Leuven and trained at KU Leuven, he pairs academic grounding with practical shipping experience across large codebases and standards-driven ecosystems.
13 years of coding experience
8 years of employment as a software developer
Master of Science (M.Sc.) Engineering: Computer Science, Master of Science (M.Sc.) Engineering: Computer Science at KU LeuvenWetenschappen-Wiskunde, Wetenschappen-Wiskunde at Sint-Donatusinstituut Merchtem
Dutch, English, French
Stackoverflow
19,859reputation
5.6mreached
315answers
0questions
html
top-1%
abstract-class
top-5%
addeventlistener
top-5%
jquery
top-5%
typescript
top-1%
java
top-5%
Github Skills (52)
asynchronous10
debug10
opacity10
javascript10
runtimes10
async10
testing10
wordpress10
css10
typescript10
templater10
template-engine10
stream10
webidl10
php10
Programming languages (25)
Github contributions (5)
microsoft/TypeScript-DOM-lib-generator
Dec 2015 - Sep 2022
Tool for generating dom related TypeScript and JavaScript library files
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:25 reviews, 52 commits, 23 PRs in 6 years 10 months
Contributions summary:Mattias primarily worked on improving the TypeScript definitions and code generation for the TypeScript DOM library generator. Their contributions include modifying data types, updating the generated code baselines, adding stream-related features based on WebIDL, and refining code structures. The user's work also encompassed fixing typos and adapting to changes in the underlying specifications. Further work on streamlining and updating the library was carried out.
javascript-libraryjavascripttypescriptdomgenerator
whatwg/streams
Dec 2017 - Oct 2022
Streams Standard
Role in this project:Back-end Developer
Back-end DeveloperContributions:183 reviews, 50 commits, 59 PRs in 4 years 10 months
Contributions summary:Mattias primarily contributed to the WHATWG Streams Standard reference implementation. Their work involved fixing various bugs related to readable byte streams and transform streams. The user's contributions focused on addressing issues with the `pipeTo()` and `tee()` methods, ensuring proper handling of backpressure, and correcting stream behavior. They also addressed issues related to async iterators, added a text encoding step to an example and fixed typo in the implementation.
javascriptstreamsstreams-standardstreamingstream
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.