About
I’m Jon Karlsen, a software engineer based in Seoul. Norwegian by birth, I’ve spent the last five years building cloud infrastructure, leading engineering teams, and shipping products across the stack — from Terraform modules to TypeScript frontends. I care about the gap between “it works” and “it’s well-built.”
Work
I was the lead software engineer at Azets, where I replaced legacy on-premise document processing with a cloud-based system (35% cost reduction), built an internal operations suite that freed 15 hours per week across departments, and introduced development workflows that tripled team velocity. Before that, I built warehouse management systems and migrated .NET applications at LittleFish.
I write TypeScript, C#, Python, and SQL. I design systems on AWS with Terraform, ship with Docker and CI/CD, and edit in Vim.
Projects
I build things outside of work. This site is one of them — a bilingual portfolio with a fitness tracking dashboard, auto-translated workout posts, and per-project GitHub stats. The others:
- Odin — GitHub/Railway mission control. Claude triages PRs and CI across every repo you care about, with real-time alerts and AI post-mortems on failed deploys.
- Haechi — Korean grammar learning app with FSRS-5 spaced repetition, AI tutor analysis, and offline-first sync.
- Training — Gym workout tracker with voice-first set logging and real-time multi-device sync.
- Algo Tutor — SRS-powered algorithm reference app for coding interview prep. 25 topics with daily email reminders.
- 우리집 — Family daily dashboard that unifies events and todos into a single stream. Built for Korean families. (WIP)
Languages
Norwegian (native), English (fluent), Swedish (fluent), Korean (intermediate). I write fitness logs in Korean several times a week and built Haechi to help with my own Korean study in Seoul.