I'm based in Tokyo, going to Japanese language school and building my own study tools on the side. Before that I spent seven years at Shopify designing shipping and fulfillment software, starting as an intern and leaving as a senior designer owning UX for projects in domains that spanned multiple teams, partnering with PM and engineering, from pitch through execution.
Actively looking for product design roles at English-friendly companies in Tokyo. Get in touch: simon.callsen@gmail.com.
Case studies
Rebuilding how stores price shipping, to match how merchants actually think about it
Making it clear how each store location is set up online
Letting stores move stock between locations, so one missing item stops blocking an order
Personal projects
A daily study dashboard that tracks textbook progress, drills vocabulary with spaced repetition, and pulls in anime, news, and generated stories for reading practice.
A Steam Deck plugin that reads Japanese text on screen, looks up each word in a dictionary, and saves them for later study — without leaving your game.
Study tool to practice conjugating Japanese verbs
Hackathon projects
Pick a kanji, see what it is made of, keep exploring. Neo4j + Daytona graph explorer with a pixel UI.
Find the best train station exits for your destination.
An agentic browser-based game.