Simon Callsen

Simon Callsen

Senior UX Designer

7 years at Shopify – now building my own tools in Tokyo.

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Case Studies
Shipping options panel listing Standard and Express ratesRate editor panel with type, price, and transit time fields
Shopify 2025

Shipping Setup Redesign

Restructured shipping rates on Shopify to better match how users actually think about shipping – while setting the stage for future feature changes

Store owners had to create a separate, disconnected setting for every price variation — four weight-based prices meant four entries with no link between them. I worked with the project's design lead to consolidate these into a single connected setting instead, shipping in stages over the past year with the same foundation still being built on today.

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Fulfillment settings panel with shipping, pickup in store, and local delivery togglesPhoto of a storefront with glass doors open to the interior
Shopify 2024

Location Delivery Methods

Simplified the experience for setting up new locations on Shopify to better communicate the different delivery methods available to them

One checkbox used to control delivery options, but depending on a store's history, checking it could silently turn on pricing the owner never chose. The redesign replaced it with a plain list showing every option's status clearly — though rolling it out meant pausing and reversing partway through, since some large stores had unknowingly built systems around the old hidden behavior.

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Order detail card showing a pickup-in-store order with a Transfer required badgeProduct photo of a packaged item from the order
Shopify 2024

Pickup in Store Extensibility

Refactored the in-store pickup feature on Shopify to allow for new use cases, while rebuilding to be fully extensible for 3rd parties

If even one item was missing from a pickup location, the whole order was blocked — even if a nearby store had it in stock, and checkout would sometimes suggest locations in the wrong country entirely. The rebuild let locations pull inventory from each other so one missing item no longer stopped an order, helping large stores finally move off outdated technology they'd been stuck on for years.

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Personal Projects

Katsuyou Drill

Study tool to practice conjugating Japanese verbs

updated 4 weeks ago
Personal Project 2025
Katsuyou Drill flip-card mode showing the verb 歩く with its English meaning and polite register
Katsuyou Drill type-answer mode showing incorrect te-form feedback for 歩く

TL;DR

Description

The goal was to build a flexible tool for language learners to drill Japanese verb and adjective conjugation.

Features

  • Conjugates verbs dynamically based on the form you select
  • Flip-card and type-answer modes with instant feedback
  • Custom card visuals for each conjugation form
  • Mobile-optimized layout

Tools

  • React + Vite
  • Vocabulary data from the JMdict dictionary project
  • Built end-to-end with Claude Code

Japanese Study

A collection of various tools to help me study Japanese

updated yesterday
Personal Project 2025
Japanese Study vocabulary training list showing weekly word lists and an SRS review queue
Japanese Study immersion reading page showing a news article with simplified text, furigana toggle, and comprehension check

TL;DR

Description

A collection of tools I built to support my own Japanese study.

Features

  • Vocabulary review with spaced repetition (SRS)
  • Immersion reading with a furigana toggle and comprehension checks

Tools

  • React + Vite
  • Supabase (backend and progress sync)
  • Built end-to-end with Claude Code
About

I spent 7 years at Shopify designing shipping and fulfillment software, starting as an intern and leaving as a senior designer.

I enjoyed working on larger problems that spanned multiple teams—taking them from initial pitch through to execution.

I'm currently based in Tokyo, going to Japanese language school, and building my own tools on the side. I'm looking for a product design role at an English-friendly company in Japan.

simon.callsen@gmail.com