Tom Fan

Software engineer on Shopify's Commerce Loop team, based in Toronto.

I work across the stack on Rails, databases, data infrastructure, and more!

Always happy to discuss awesome projects, new tools, and the next fascinating problem.

Contact Me

Email: [email protected] GitHub: @CATBOYCOWBOY LinkedIn: @tom-8-fan My CV

About

I'm a software engineer at Shopify in Toronto. I started there as an intern in 2023 and joined full time in May 2026, after finishing my computer science degree at Carleton University.

I care a lot about good code: code that's easy to read, easy to change, and that the next person can pick up without a walkthrough. I'm also big on agentic coding, where AI agents write and test code alongside me. What interests me most is the hard part: figuring out how to hold that code to the same standard as everything else.

Away from the monitor, I love physical craft and the outdoors. On weekends you'll find me running, building (irl), or skiing up and down the Ice Coast.

Work

Commerce Loop 2026 – now

I shipped Stock counts, which lets merchants count their inventory natively in Shopify Admin instead of through an app. It launched to everyone on October 18. I built the backend services that write approved counts to the inventory ledger, designed the data layout in YugabyteDB, and wrote the React screens merchants use to review a count. Much of the work came down to compare-and-swap consistency and idempotency. I also led an effort to shrink one of our busiest database tables from 1 TB to 450 MB.

Stateful Services 2025 – 2026

This team runs Shopify's MySQL, Redis, and Memcached fleets. The changes I made to how our database hosts use disk space now save over $2 million a year. I also wrote Go tooling that lets engineers block bad queries at the proxy layer during an incident, and automated our MySQL writer failover for when a Google Cloud zone goes down.

Analytics 2023 – 2024

I worked on the GraphQL APIs behind the analytics pages in Shopify Admin and on ShopifyQL, the query language merchants use to build their own reports. I also helped rework Admin's frontend routing so AI assistants could plug into it. Looking back, that's still one of my favourite projects.

Misc