jamell.dev

About

I'm a full stack engineer based in Tokyo, Japan, currently working on production reliability and infrastructure modernization.

My path here went basically like: an associate's degree in Control Systems Engineering at the National Institute of Technology, Sasebo College (2020–2023), then a bachelor's in Computer Science and Intelligent Systems at Oita University (2023–2025). Along the way I picked up backend and full stack internships, Flask web app at Sigma-i for local governments' data needs, a route-search app built on bus GTFS-RT data at MobileCreate.

What I work on

Most of my time goes into keeping legacy production services healthy while they get modernized. That's meant leading Spring Boot 3.x upgrades across several services, breaking dependency changes, deprecated API migrations, pushing test coverage to reasonable pcts, and performance testing along the way. It's also meant spearheading the migration of 1,600+ cron jobs off bare-metal VMs onto Kubernetes using Apache Airflow, with logging, error propagation, and a CI/CD pipeline for DAG generation.

A good chunk of the job is also just chasing down slow things: profiling high-traffic services, then rolling out OpenTelemetry and performance-testing tooling once I find the bottleneck.

Outside of work

I like building infrastructure for myself as much as for my day job. This site runs on a small self-hosted platform I maintain on a single VPS — Caddy in front, Zitadel for SSO, everything else in Docker. The centerpiece is Marsa, a minimal self-hosted PaaS I built to replace Coolify: it deploys Docker Compose apps with automatic TLS, GitHub push-to-deploy, Zitadel-backed SSO, JWT-protected APIs, and a goroutine-based async deploy worker pool underneath. I've also shipped smaller things like an Android app for offline kanji lookup using the KANJIDIC2 dictionary, unimaginatively named "WhatsThisKanji" .

Day to day I mostly reach for Java, Go, Python, and TypeScript, with Spring Boot, React/Next.js, Docker, and Kubernetes as the usual stack. I speak English, French, and Arabic fluently, and Japanese well enough to work in it day to day.

Elsewhere