This is not Kotlin DSL, you are just using regular old Groovy. Best way would be to put it all inside a Dependencies.kt file inside your buildSrc/ folder. See e.g. https://medium.com/@wzieba/an-argument-against-buildsrc-defined-dependencies-or-how-to-seamlessly-keep-your-gradle-8e0bfd7ee8e3 for more information.