Selected work

Projects


I build tools that help teams ship with confidence, software that supports real courses, and the platform underneath this portfolio.

01 · Product

Developer tools

Greenroom run dashboard showing browser checks across environments, with passed, failed, and pending results.

For product teams and developers

Greenroom

Turn a live web app into repeatable browser checks. When something breaks, Greenroom bundles the trace, video, screenshots, logs, and a written summary so developers can reproduce the issue.

I built it as a local app and a deployable team platform. Its committed seeded report lets you inspect a passing run and an intentional failure without mistaking either for live customer data.

02 · Open source systems

The platform behind this site

03 · Education

Teaching technology

Course Console demo showing a GitHub-based course workspace.

For instructors and software engineering students

GitHub-Native Course Platform

I designed and built a course platform around the tools students use to learn software engineering. Course materials, submissions, feedback, and grading fit into a GitHub workflow instead of asking students to learn a separate system.

Built and run in production across several live university courses, covering hundreds of student repositories each term. The public source describes the operating model; the demo uses invented classes, with no student data or token.

I also teach these courses. See the courses, assessment approach, and badge criteria.

Part of tjakoen.github.io, built with itself.

AI helps me write and review. I direct the work, test the result, and answer for what ships. How I work with AI →