A major addition to the Java ecosystem when dealing with Scala is Simple Build Tool (SBT), a flexible build system written in Scala that also powers both Typesafe Activator, which we used in the previous chapters, and the Play framework that we will cover later on in this book. In contrast to the existing XML formats used by Ant and Maven in Java environments, SBT build definitions are written in Scala in the form of a Domain Specific Language (DSL), having the benefit of compile-time checking. As we will see in this section, SBT provides a number of additional convenient features. In addition to its dependency management ability based on Ivy and supporting Maven-format repositories, SBT offers both incremental compilation and an interactive shell (that is, the REPL we were using earlier). It also supports continuous testing and deployment, and integrates with many Scala test frameworks, making it the de facto build tool for the Scala community.