The book is dedicated to the development of mobile applications for Android in the Kotlin language. The basic elements of the language are considered, such as functions and classes, and object-oriented programming techniques. Describes the development of RESTful microservices for Android applications and methods for implementing the MVC architecture pattern. Methods for centralizing, transforming and storing data using Logstash and protecting applications using Spring Security are described. Learns how to manage dependencies using Kotlin. Attention is paid to the deployment of Kotlin microservices for AWS and Android applications in the Play Store.