Under the River

It’s a strange time to be working in developer tools. Things we were doing six months ago don't make sense anymore. Tools that didn't exist a year ago are now central to how we work. The texture of the job has never changed so fast, and the tools we’re building reflect that. River is an AI agent that lives in our company Slack. We launched it a couple of months ago. Now, one in eight merged pull requests across Shopify is coauthored by it. Tobi shared how River has become a teaching workshop for our company, but the agent surface layer is only one part of the story. This is what we built underneath River, and the bet we placed in early 2024 that made it all possible. Here’s where Shopify was: many repos, bespoke development environments, slow feedback. Friction we’d learned to live with, especially when the alternative was "rewrite everything." Become a monorepo company. One repository for all things Shopify ships. We call it World. Build everything with Nix. Dev environments, CI, production images: one reproducible substrate. These were not crowd-pleasers. They were infrastructure-hygiene moves some thought were a waste of effort. But a bet drove them: “Code…