The book is dedicated to the development of mobile applications for Android in the Kotlin language. The main elements of the language are considered, such as functions and classes, object-oriented programming techniques. Describes the development of RESTful microservices for Android applications, methods for implementing the MVC architecture template. Describes how to centralize, transform, and store data using Logstash, application protection using Spring Security. Learn how to manage dependencies with Kotlin. Attention is paid to the deployment of Kotlin microservices for AWS and Android applications in the Play Store.