Jonathan De Halleux
Principal Software Development Engineer at Microsoft
Seattle, Washington, United States
Summary
🤩
Rockstar🎓
Top SchoolJonathan De Halleux is a Principal Software Development Engineer at Microsoft with over a decade of experience building developer tools, education-focused platforms and IoT runtimes. He founded Microsoft MakeCode and continues to lead projects like GitHub Agentic Workflows, Jacdac and GenAIScript—bridging research-grade applied mathematics (PhD) with pragmatic product engineering. His contributions span full stack work on influential projects such as TouchDevelop and pxt-arcade, where he’s enhanced UI/UX, simulator engines and tiny-device TypeScript support. Based in Seattle, he combines deep systems and testing expertise (including .NET JIT work) with a knack for making programming accessible to learners and makers. An unusual strength is his ability to move fluidly between research, tool-building and shipping production-quality developer experiences.
11 years of coding experience
6 years of employment as a software developer
PhD Applied Mathematics, PhD Applied Mathematics at Université catholique de Louvain
French, English, Spanish
Github Skills (21)
javascript10
game-engine10
game-dev10
typescript10
ui-design10
uid10
front-end-development10
typescript-types10
html10
blockly10
docusaurus10
typescripts10
game-development10
react10
api-design9
Programming languages (21)
Github contributions (5)
microsoft/TouchDevelop
Feb 2015 - May 2018
TouchDevelop is a touch-friendly app creation environment for iPad, iPhone, Android, Windows, Mac, Linux. Our mobile-friendly editor makes coding fun, even on your phone or tablet!
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:2297 commits, 39 PRs, 1313 pushes in 3 years 3 months
Contributions summary:Jonathan was involved in multiple aspects of the microsoft/touchdevelop repository, contributing to both front-end and potentially back-end functionalities. The commits demonstrate involvement in UI/UX changes, specifically concerning the display of the application's features, as well as changes to core functionalities such as radio data. The code changes also show the user's involvement in testing and debugging.
ipadphoneiphonewindowstablet
microsoft/pxt-arcade
Mar 2018 - Jan 2023
Arcade game editor based on Microsoft MakeCode
Role in this project:Back-end Developer
Back-end DeveloperContributions:26 reviews, 1106 commits, 709 PRs in 4 years 11 months
Contributions summary:Jonathan's commits primarily focused on the `sim/simulator.ts` and `sim/api.ts` files, indicating a role in enhancing the game engine's core functionalities. Their work included implementing features for screenshot capture, utilizing a title from the message, and allowing the game engine to trigger screenshots. They also worked on cloning game APIs into `pxt-32`, suggesting an effort to replicate and integrate game logic.
arcade-gamearcadegame-editorgame-developmentmicrosoft
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