How to learn Kotlin

The 2026 Kotlin Learning Roadmap

Here’s a structured, phase-by-phase approach to go from beginner to job-ready or proficient hobbyist.

Phase 1: Foundation & Setup (Weeks 1-2)

Goal: Understand why Kotlin and set up your development environment.

1. Why Kotlin in 2026?
   • Android First: The official, recommended language for Android. Most new Android jobs require it.
   • Multiplatform (KMP): This is the big trend. Write business logic once, run it on Android, iOS, Web, and Desktop. Huge demand is projected for 2026 and beyond.
   • Backend: Excellent with frameworks like Ktor and Spring Boot (which has fantastic Kotlin support).
   • Concise & Safe: Less boilerplate code than Java, with built-in null safety to prevent common errors.
2. Set Up Your Environment:
   • IDE: Install IntelliJ IDEA Community Edition (free). It’s made by JetBrains, the creators of Kotlin, so the support and tooling are first-class.
   • JDK: Install a JDK 17 or 21 (Long-Term Support versions). IntelliJ will often guide you through this.
3. Your First Program:
   • Create a new Kotlin project in IntelliJ and write the classic Hello, World! program. Get comfortable running code in the IDE.

Phase 2: Core Kotlin Syntax & Concepts (Weeks 3-6)

Goal: Master the fundamentals. Don’t just copy code; understand the concepts.

• Basic Syntax: Variables (val vs var), basic types (String, Int, Boolean), functions (fun), and control flow (if, when, for, while).
• Null Safety: This is critical! Understand nullable types (String?) and safe calls (?.), the Elvis operator (?:), and the non-null assertion (!!).
• Collections: List, Set, and Map. Learn the difference between read-only and mutable versions (List vs MutableList).
• Object-Oriented Programming (OOP):
  • Classes, constructors, properties.
  • Inheritance (open keyword), interfaces.
  • Data Classes (data class): A Kotlin superstar for holding data.
  • Object Declarations (object): For Singletons.
• Functional Programming in Kotlin:
  • Lambdas and Higher-Order Functions.
  • The powerful standard library functions: .map, .filter, .let, .apply, .also, .run.

Recommended Resources for Phase 2:

• Official Kotlin Docs: The Kotlin Docs are fantastic. Start with “Kotlin Basics”.
• JetBrains Academy: Their Kotlin Basics Track is a hands-on, project-based learning platform. Highly engaging.
• Book: Kotlin in Action by Dmitry Jemerov and Svetlana Isakova. It’s a classic and still highly relevant.

Phase 3: Choose Your Path & Build Projects (Weeks 7-12+)

This is where you specialize. Pick one path to start, build a few projects, and then you can explore others.

🎯 Path A: Android Development (The Most Popular Path)

• Learn Modern Android Development:
  • Jetpack Compose: This is the present and future of Android UI. Do not start with the old XML-based UI system. In 2026, Compose will be the standard.
  • Architecture: Learn about ViewModels, Room (database), Retrofit (networking), and the recommended app architecture (e.g., MVVM).
• Resources:
  • Official Android Developers Codelabs: Look for “Compose” and “Kotlin” codelabs. They are the best, most up-to-date tutorials.
  • Android Basics in Kotlin: A free course by Google.
  • YouTube: Channels like Philipp Lackner, Coding with Mitch, and Stevdza-San offer excellent, modern tutorials.
• Project Ideas:
  1. A simple note-taking app.
  2. A weather app that fetches data from a free API.
  3. A habit tracker.

🖥️ Path B: Backend Development

• Pick a Framework:
  • Ktor: A lightweight, asynchronous framework built by JetBrains. Great for learning Kotlin’s coroutines.
  • Spring Boot: The giant in the Java ecosystem. It has excellent Kotlin support, making code more concise and idiomatic.
• Key Concepts:
  • Coroutines: For asynchronous, non-blocking code. Essential for modern backends.
  • Dependency Injection (e.g., Koin or Spring’s own).
  • Connecting to Databases (e.g., Exposed for SQL, MongoDB driver).
• Resources:
  • Official documentation for Ktor or Spring Boot.
• Project Ideas:
  1. A REST API for a simple blog.
  2. A URL shortener service.
  3. A real-time chat application using WebSockets.

🌐 Path C: Kotlin Multiplatform (KMP) – The “Future-Proof” Path

• Concept: Share business logic (networking, data models, validation) between Android, iOS, and Web.
• Tech Stack:
  • Shared KMP Module: Contains the common logic.
  • Android: Uses Jetpack Compose.
  • iOS: Uses SwiftUI for the UI, calling into the shared Kotlin code.
• Resources:
  • The official Kotlin Multiplatform Docs are your starting point.
  • Touchlab and Kodeco have excellent advanced articles and videos.
• Project Idea: Build a simple app (like a currency converter or a todo list) that runs on both Android and iOS from a single codebase for the logic.

Phase 4: Advanced Topics & Best Practices (Ongoing)

Goal: Elevate your code from “working” to “professional.”

• Coroutines & Flows: Deep dive into concurrency. Understand Flow and StateFlow for reactive streams of data.
• Dependency Injection: Master a library like Koin or Dagger/Hilt (for Android).
• Testing: Write unit tests for your functions and ViewModels. Use MockK for mocking.
• Code Style & Conventions: Follow the official Kotlin Coding Conventions.
• Version Control: Use Git & GitHub for all your projects.

Key Mindset & Tips for 2026

1. Code Daily: Consistency is more important than long, infrequent sessions.
2. Build, Build, Build: Tutorials are a starting point. True learning happens when you build your own projects and solve your own problems. Don’t get stuck in “tutorial hell.”
3. Embrace the Community:
   • Follow Kotlin and Android developers on Twitter/X and Mastodon.
   • Join the Kotlin Slack and r/Kotlin on Reddit.
4. Read Code: Explore open-source Kotlin projects on GitHub to see how experienced developers structure their code.
5. Stay Updated: The tech world moves fast. Follow the Kotlin Blog for announcements about new versions (Kotlin 2.x+) and features.

Summary of Your 2026 Toolkit

By following this roadmap, you’ll not only learn Kotlin but also position yourself with skills that will be highly valuable in 2026, especially in the growing fields of Android and Kotlin Multiplatform. Good luck.