The scope of Etsy's frontend is massive - our JavaScript codebase has grown by 50% in the last year to more than 3,000 files totaling almost 800,000 lines. Because of Etsy's dedication to continuous deployment, the code running in production changes 25 to 50 times every day. Because of our experimentation-driven development cycle, there may be multiple production versions of our features at any given time. These factors can lead to uncertainty and fear with rolling out upgrades, deleting old code, or confidently making changes. We'll see how the Frontend Infrastructure team works within this ecosystem to mitigate those risks, manage the asset build pipeline, builds tools to understand our frontend, automates migrations & deletes as much code as possible.