Professional Kotlin: Advanced Techniques

This book is not another introduction to syntax. "Professional Kotlin: Advanced Techniques" is created for developers who already write confidently in Kotlin but want to reach a new level of mastery. The author, Alexey Voronov, a Senior Developer with 10 years of experience, shares techniques that are rarely found in tutorials and documentation.

What is this book about?

You will dive into the most complex and powerful features of the language:

• Coroutines and Channels: a detailed breakdown of Structured Concurrency, Flows, Channel, and building reactive pipelines.
• Type-safe Builders and DSLs: creating your own domain-specific languages for tests, configuration, and UI.
• Inline Functions and reified: how to use generics at the bytecode level and avoid overhead.
• Metaprogramming: reflection, annotations, KSP, and compiler plugins.
• Functional Style: monads, immutability, function composition without performance loss.
• Multithreading Without Pain: SharedFlow, Mutex, Actor, and concurrency access patterns.

Who is this book for?

• Android developers looking to build fast and reliable applications.
• Backend engineers working with Ktor or Spring WebFlux.
• Tech leads and architects introducing Kotlin into legacy projects.
• Java developers who want to master Kotlin at a professional level.

What will you learn?

• How to design APIs using covariance and contravariance.
• Why sealed classes and sealed interfaces change the approach to architecture.
• How to optimize memory with value classes and inline classes.
• Real-world cases: from JSON parsing to building an Event Sourcing system.
• How to write tests for coroutines and custom Scopes.

Each chapter contains practical examples ready for use in production projects. The code is available in a GitHub repository. After reading, you will be able not only to read complex code written by others but also to create your own libraries in Kotlin.

Ideal for those who want to stop "just writing in Kotlin" and start using it to its full potential.