Apollo Kotlin is a type-safe, caching GraphQL client that allows developers to work with GraphQL queries and mutations in a more efficient and scalable way. It has been refactored to support Fragments as Interfaces, which enables the generation of models that map 1:1 with the JSON response, making it easier to work with complex data structures. Apollo Kotlin also introduces new features such as coroutine APIs for easier concurrency, multiplatform support, and improved caching mechanisms. The client can be used with any Kotlin-based application, website, or server. It is available on Maven Central and has been designed to provide a more idiomatic Java API for those who prefer it over the Kotlin-first approach.