Move fast and automatically refactor things. That's my dream at least. Scalafix is a new tool to create "rewrites" that refactor Scala code. Rewrites are composed of "patches", which is a small algebra of operations that can be assembled to run as a single refactoring step. The long-term goal of scalafix is to help automate the migration of Scala 2.x features to Dotty. In this talk, we'll learn how scalafix is implemented on top of scala.meta and how to write custom rewrites for ad-hoc library and application migrations. We'll also compare scalafix with the current landscape of Scala tooling.