Netflix's open source tools have pioneered the world of cloud builds and deployments. Nebula, Netflix's Gradle-based build tool, is used by every project at Netflix. Spinnaker, is Netflix's global cloud delivery platform, orchestrating hundreds of deployments to the cloud daily. As our tools continue to mature and evolve, the Engineering Tools team is always looking for ways to improve them. Innovations in the JVM language space are one avenue we've experimented with recently, and that led us to Kotlin. In this talk, Robert Fletcher (Senior Software Engineer) shares the team’s stories of how Kotlin is being used to evolve the existing fleet of build and deployment tools; Nebula and Spinnaker. He also talks about the next generation of tools we are building, that lean heavily on Kotlin. Rob Fletcher is a senior engineer at Netflix and part of the Spinnaker team. He has been a professional software engineer for almost two decades and is the author of O'Reilly's Spock: Up and Running. Danny Thomas is a member of the Netflix Developer Productivity team, focusing on all things build and dependency management. 20-year industry veteran, with a background in systems, network, and performance engineering.