A few months after launching v2.0 of MailChimp’s API, it was already falling short of our expectations. In every area, problems were slowing our users down and getting in their way. After finding our attempts to fix the problems uninspiring, we decided to start over. In this workshop we’ll walk you through our processes (from evaluation of v2.0 through implementation of v3.0) and share the lessons we learned while trying to fix an API that serves more than a billion requests per month. Join us for this crash course on building an API optimized for developer happiness.