Shopify changes a lot. We merge around 400 commits to the main branch daily and deploy a new version of our core monolith 40 times a day. The Monolith is also big: 37,000 Ruby files, 622,000 methods, more than 2,000,000 calls. At this scale with a dynamic language, even with the most rigorous review process and over 150,000 automated tests, it’s a challenge to ensure everything works properly. Developers benefit from a short feedback loop to ensure the stability of our monolith for our merchants. Since 2018, our Ruby Infrastructure team has looked at ways to make the development process safer, faster, and more enjoyable for Ruby developers. While Ruby is different from other languages and brings amazing features allowing Shopify to be what it is today, we felt there was a feature from other languages missing: static typing. ​​​​​​​During this event you will learn - Why we use Sorbet for static typing - What it means to treat typing as a product - What supporting tools we built - How we measure the effectiveness of gradual typing - What lessons we learned