We talked to Ole Sasse and Gregor Zeitlinger, Senior Engineers at Zalando and leaders of their “Kotlin Guild”, about the weather in Spain and Germany, but more importantly, about how Zalando has successfully introduced Kotlin on the server-side. Ole and Gregor talk about the way that Kotlin engineers organize themselves inside Zalando, using their “Guild” model which allows engineers across different teams to share knowledge with each other and learn about new and more complex topics and libraries together. In addition to Android and frontend, Zalando’s logistics department uses Kotlin to build server-side microservices. We learned about the frameworks their engineers use, including Spring and Ktor, and how Kotlin was first introduced at Zalando and integrated seamlessly with their pre-existing custom libraries, earning an “Adopt” spot in Zalando’s Tech Radar (https://opensource.zalando.com/tech-radar/). Together, we also tackled one of the classic questions about Kotlin: how do you get people on board? Gregor shared his insights on the topic, and how to get people to have their first “a-ha” moment with Kotlin, and Ole chimed in with more information on convincing Scala versus Java developers. We also learned why most teams using Kotlin for the backend prefer to write their whole services in Kotlin code, and saw the contrast with Zalando’s mobile application development, among many other topics. Explore more about Kotlin and Zalando: Zally, A minimalistic, simple-to-use API linter from Zalando: https://github.com/zalando/zally “How we use Kotlin for backend services at Zalando”: https://engineering.zalando.com/posts/2021/07/kotlin-for-backend-services.html Do Kotlin at Zalando: https://jobs.zalando.com/en/jobs/?search=kotlin Zalando Engineering: https://engineering.zalando.com/