Master Kotlin with Modern Architecture, Coroutines, KMP, Compose, and Professional Backend
This 2025 edition of Learn Kotlin is the complete and updated guide for professionals and students who want to master the Kotlin language with technical depth and practical focus. Expanding and fully refining the content of the previous edition, this manual introduces a new modular structure with optimized chapters, clear explanations, and direct application of concepts in multiple professional contexts.
You will learn to program in Kotlin from scratch to an advanced level, gaining real mastery of its modern applications—mobile, backend, multiplatform, and reactive systems. The book covers everything from language fundamentals to strategic topics such as Kotlin Multiplatform (KMP), Jetpack Compose, coroutines, REST API integration, persistence with Room, automated testing, library publishing, and backend development with Ktor.
Includes:
Full development environment setup with IntelliJ and Android Studio
Basic syntax, functions, collections, object-oriented programming, and functional programming
Concurrency and parallelism with coroutines, async, await, withContext, and Dispatchers
REST API consumption and publishing with Retrofit, Ktor, and JWT authentication
Persistence with SQLite and Room, data modeling, and advanced queries
Unit and integration testing with JUnit 5, MockK, and validation strategies
Code sharing across Android, iOS, and backend with KMP and expect/actual
Building modern interfaces with Jetpack Compose and reactive navigation
Kotlin project publishing to Maven Central with Dokka and professional versioning
Scalable architecture, code standards, design patterns, and industry best practices
By the end, you will be fully prepared to work professionally with Kotlin in any scenario—mobile, backend, distributed systems, multiplatform, and modern projects based on coroutines, reactive architecture, and real integration with cutting-edge tools.
kotlin, kotlin multiplatform, android development, coroutines, ktor, compose, rest api, room, modern architecture, functional programming, automated testing, maven publishing, dokka, kotlin backend, advanced kotlin.
Diego Rodrigues
Technical Author and Independent Researcher
ORCID: https://orcid.org/0009-0006-
StudioD21 Smart Tech Content & Intell Systems
Email: [email protected]
LinkedIn: www.linkedin.com/in/
An international technical author (tech writer) focused on structured production of applied knowledge. Founder of StudioD21 Smart Tech Content & Intell Systems, where he leads the creation of intelligent frameworks and the publication of didactic technical books supported by artificial intelligence, such as the Kali Linux Extreme series, SMARTBOOKS D21, among others.
Holder of 42 international certifications issued by institutions such as IBM, Google, Microsoft, AWS, Cisco, META, Ec-Council, Palo Alto, and Boston University, he operates in the fields of Artificial Intelligence, Machine Learning, Data Science, Big Data, Blockchain, Connectivity Technologies, Ethical Hacking, and Threat Intelligence.
Since 2003, he has developed over 200 technical projects for brands in Brazil, the USA, and Mexico. In 2024, he established himself as one of the leading technical authors of the new generation, with more than 180 titles published in six languages. His work is based on his proprietary applied technical writing protocol TECHWRITE 2.2, aimed at scalability, conceptual precision, and practical applicability in professional environments.