Kotlin 2.2.10

Online Kotlin Compiler & Editor

Name: myCompiler Kotlin
Author: myCompiler

myCompiler is a free online Kotlin compiler, editor and code runner that lets you write, run, and share Kotlin code directly in your browser. It works as your Kotlin playground, sandbox, fiddle, cloud compiler, and online REPL. No downloads, no installation needed. Just open the editor and start coding with syntax highlighting, autocomplete, and instant output.

Start coding in Kotlin How it works

27+ languages Used by 1M+ developers Free forever

main.kt

data class User(val name: String, val age: Int)

fun main() {
    val users = listOf(
        User("Alice", 25),
        User("Bob", 30),
        User("Charlie", 35)
    )

    users.filter { it.age >= 30 }
        .forEach {
            println("${it.name}: ${it.age}")
        }
}

Output

Bob: 30 Charlie: 35

How to run Kotlin code online

Three steps to go from idea to running Kotlin code in this online playground. No account required.

Write your code

Open the Kotlin editor and start writing. The smart editor gives you syntax highlighting, autocomplete, and error detection as you type.

Click Run

Hit the Run button or press +Enter to run your Kotlin code on secure, sandboxed cloud servers.

See results

Output appears instantly in the integrated terminal. Errors and exceptions show up with clear, helpful messages.

Everything you need to code in Kotlin

A complete online Kotlin IDE and coding playground in your browser. Write, run, and share code without any setup.

Zero setup required

Start coding in seconds with this browser-based Kotlin interpreter. No downloads, no installations, no environment configuration. Open your browser, go to myCompiler, and start writing Kotlin code immediately.

Works on any device with a web browser. Desktop, laptop, tablet, phone, Chromebook. There is nothing to install and nothing to configure.

Feature-rich code editor

Write Kotlin with a professional-grade code editor built into your browser. Syntax highlighting colors your code for readability, making keywords, strings, and functions easy to distinguish at a glance.

Intelligent autocomplete suggests methods and properties as you type, and real-time error detection catches mistakes before you run your code.

Multi-file projects

Create and manage multiple files in a single project. Use the file sidebar to organize your code into modules, then import them across files just like in a desktop IDE.

Build modular applications with proper project structure. Each file is editable, and you can switch between them instantly.

Run code instantly

Click the Run button or press +Enter to execute your Kotlin code instantly. This online code runner displays output immediately in the integrated terminal panel. Your code runs on secure, sandboxed cloud servers and results appear in seconds.

Error messages and tracebacks are displayed clearly, making it easy to find and fix issues. The terminal supports ANSI colors for rich output formatting.

Ready to try it? Write and run your first Kotlin program in seconds.

Open Kotlin editor

Kotlin on myCompiler

myCompiler runs Kotlin 2.2.10, always up to date with the latest stable release. You get a full browser-based IDE with syntax highlighting, intelligent code completion, multi-file project support, a built-in terminal for real-time output, and standard input (stdin) for interactive programs. Write, compile, run, and debug Kotlin code on any device. Desktop, laptop, tablet, phone, Chromebook. Zero downloads, zero configuration, and no sign-up required. Save your programs with a unique URL and share them with anyone. You can also embed a working Kotlin editor on your own website.

Use this online Kotlin playground as a quick code executor for testing snippets, a coding sandbox for learning, or a cloud compiler for coding interview preparation. The editor includes dark mode for comfortable coding, keyboard shortcuts for faster workflows, and clear error messages with line numbers so you can debug quickly. Students use it for homework and practice. Teachers use it to share working examples. Developers use it to prototype ideas. myCompiler is beginner-friendly, fast, and completely free. It works in any modern web browser.

Start coding in Kotlin

Kotlin code examples

Common Kotlin patterns you can try in the online compiler. Each example is ready to run.

Hello World in Kotlin

main.kt

fun main() {
    println("Hello, World!")
}

Variables and Data Types in Kotlin

main.kt

fun main() {
    val name: String = "Alice"
    var age: Int = 30
    val height: Double = 5.6
    println("$name is $age years old")
}

If-Else Conditionals in Kotlin

main.kt

fun main() {
    val x = 10
    if (x > 0) println("Positive")
    else if (x == 0) println("Zero")
    else println("Negative")

    val result = when {
        x > 0 -> "positive"
        x == 0 -> "zero"
        else -> "negative"
    }
    println(result)
}

For and While Loops in Kotlin

main.kt

fun main() {
    for (i in 1..5) println("Count: $i")

    val fruits = listOf("apple", "banana", "cherry")
    for (fruit in fruits) println(fruit)
}

Functions in Kotlin

main.kt

fun greet(name: String, greeting: String = "Hello"): String {
    return "$greeting, $name!"
}

fun main() {
    println(greet("Alice"))
    println(greet("Bob", "Hi"))
}

Arrays and Collections in Kotlin

main.kt

fun main() {
    val fruits = mutableListOf("apple", "banana", "cherry")
    fruits.add("date")
    println(fruits[1])

    val person = mapOf("name" to "Alice", "age" to 30)
    println(person["name"])
}

Classes and Objects in Kotlin

main.kt

data class Dog(val name: String, val breed: String) {
    fun bark() = "$name says Woof!"
}

fun main() {
    val dog = Dog("Rex", "Labrador")
    println(dog.bark())
    println(dog.copy(name = "Max").bark())
}

Error Handling in Kotlin

main.kt

fun main() {
    try {
        val num = "abc".toInt()
    } catch (e: NumberFormatException) {
        println("Error: ${e.message}")
    } finally {
        println("Done")
    }
}

File I/O in Kotlin

main.kt

import java.io.File

fun main() {
    File("output.txt").writeText("Hello, File!")
    val content = File("output.txt").readText()
    println(content)
}

Coroutines in Kotlin

main.kt

import kotlinx.coroutines.*

suspend fun fetchData(id: Int): String {
    delay(100)
    return "Data for item $id"
}

fun main() = runBlocking {
    val results = (1..3).map { id ->
        async { fetchData(id) }
    }
    results.awaitAll().forEach { println(it) }
}

Try these examples in the editor

How to take input in Kotlin online

myCompiler supports standard input (stdin) for Kotlin programs. Use Kotlin's standard input functions to read user input. Enter your input data in the stdin panel before running your program.

This works for both single-line and multi-line input. You can read strings and convert to numbers using the language's built-in I/O functions.

Try it yourself

main.kt stdin supported

fun main() {
    val name = readLine()!!
    val age = readLine()!!.toInt()

    println("Hello $name!")
    println("You'll be ${age + 1} next year.")
}

stdin

Alice
25

Output

Hello Alice!
You'll be 26 next year.

No setup, no sign-up. Start writing Kotlin code right now.

Start coding now

Getting started with Kotlin online

You can start writing and running Kotlin code right now without installing anything. Type your code, and click Run. This free Kotlin code runner executes your program instantly and displays the output in the terminal panel below the editor. Open the Kotlin online editor, type your code, and click Run.

If you're new to Kotlin, use this online Kotlin playground to start with the basics like variables, data types, conditionals, and loops. The code examples above cover all the fundamentals you need to get started. Each example can be copied into the sandbox and run immediately. No setup, no configuration.

As you progress, try creating multi-file projects, using libraries, and sharing your programs with others via URL. Sign up for a free account to save your work and build a personal library of programs. myCompiler works as a full online Kotlin IDE right in your browser.

Who uses myCompiler

Whether you're learning to code, preparing for interviews, or prototyping ideas, myCompiler is built for you.

Students & Learners

Practice exercises, complete homework assignments, and experiment with code without installing anything on school or personal computers.

Teachers & Educators

Share code examples with students via unique URLs. Embed the compiler in course materials so students can run examples directly in the browser.

Interview Candidates

Practice coding interview problems, test algorithms, and verify solutions quickly during preparation for technical interviews.

Professional Developers

Quickly prototype ideas, test code snippets, or try out a library without setting up a local environment. Great for quick experiments.

Content Creators & Bloggers

Embed interactive examples in blog posts, tutorials, and documentation so readers can run code without leaving the page.

Teams & Collaborators

Share code snippets with colleagues via URLs. Others can view, run, and fork your code to build on your work.

myCompiler vs. local IDE

Why use an online Kotlin compiler instead of installing one locally?

Feature	myCompiler	Local IDE
Setup time	Instant	Minutes to hours
Installation	None required	Kotlin + IDE required
Device support	Any browser	Desktop only
Sharing code	One-click URL	Manual (file, git, etc.)
Languages	27+ in one place	One at a time
Cost	Free forever	Free to $$$
Works on Chromebook	Yes	Limited

What is Kotlin?

Kotlin is a modern, statically typed programming language developed by JetBrains (the company behind IntelliJ IDEA) and first released in 2011. In 2017, Google announced Kotlin as an official language for Android development, and in 2019 declared it the _preferred_ language for Android, a massive endorsement that drove Kotlin's adoption across the industry.

Kotlin is fully interoperable with Java, you can call Java code from Kotlin and vice versa, use Java libraries, and mix Kotlin and Java files in the same project. Kotlin's key improvements over Java include null safety (eliminating NullPointerExceptions at compile time), extension functions, data classes, coroutines for async programming, and significantly less boilerplate code.

What is Kotlin used for?

Kotlin is used for Android app development, the majority of new Android apps are written in Kotlin, server-side development with Ktor and Spring Boot (both have first-class Kotlin support), multiplatform development via Kotlin Multiplatform (sharing business logic between Android, iOS, and web), and scripting with Kotlin scripts (.kts files). Jetpack Compose, Google's modern Android UI toolkit, requires Kotlin.

Kotlin for beginners

Kotlin is an excellent language for Android development beginners and for Java developers making the transition to a more modern language. Its null safety prevents the most common class of Android crashes, and its concise syntax reduces boilerplate significantly. Use myCompiler's online Kotlin compiler to practice Kotlin syntax, data classes, extension functions, and coroutines without installing Android Studio or the JDK.

Kotlin vs other languages

Compared to Java, Kotlin is more concise, has built-in null safety, and is the preferred language for Android development. The two are fully interoperable on the JVM. Compared to Swift (iOS counterpart), Kotlin and Swift share many modern language features (optionals/null safety, closures, data classes/structs), Android/Kotlin and iOS/Swift are parallel career paths. Compared to Dart/Flutter, Kotlin targets Android natively while Flutter is a cross-platform framework.

Why use an online Kotlin compiler?

An online Kotlin compiler, also called a Kotlin playground or JVM sandbox, lets you compile and run Kotlin code directly in your browser without installing Android Studio or the JDK. This is ideal for learning Kotlin syntax, practicing data classes and extension functions, understanding coroutines, and preparing for Android or Kotlin backend interviews.

myCompiler's online Kotlin IDE runs Kotlin on the JVM with the full Kotlin standard library and access to Java's standard library. Coroutines, data classes, sealed classes, and all modern Kotlin features are supported. Save and share programs via URL, completely free.

Why is Kotlin so popular?

Kotlin's rise is primarily driven by Android's official endorsement. With Android running on billions of devices and Google making Kotlin the preferred language, every Android developer now works in Kotlin. Beyond Android, Kotlin's clean syntax and JVM interoperability have made it popular for server-side development. The Kotlin Multiplatform initiative aims to extend Kotlin to iOS, web, and desktop, which could significantly broaden its reach.

Kotlin career opportunities

Kotlin is essential for Android developer roles and increasingly sought for backend developer, full-stack developer, and Kotlin Multiplatform developer positions. Android development demand remains strong as mobile apps continue to be central to business strategy. Combined with Jetpack Compose knowledge, Kotlin expertise is one of the most in-demand mobile development skill sets.

Try Kotlin online Free · No sign-up needed

Keyboard shortcuts

Code faster with these keyboard shortcuts in the myCompiler editor.

Run code

+ Enter

Save program

+ S

Toggle comment

+ /

Indent line

Tab

Unindent line

Shift + Tab

Undo

+ Z

Select next occurrence

+ D

Find & replace

+ H

Embed the Kotlin compiler on your website

Add an interactive Kotlin compiler to your website, blog, or learning platform. Readers can write and run Kotlin code directly on your page without leaving it.

Perfect for technical tutorials, coding courses, documentation, and educational content. Save a program on myCompiler and use the embed link to add it to any webpage.

Embedded Kotlin compiler, editor and code runner

HTML

<iframe
src="https://www.mycompiler.io
    /embed/kotlin"
width="100%"
height="400"
frameborder="0">
</iframe>

Why developers choose myCompiler

A full-featured online IDE for Kotlin and 27+ other programming languages.

27+ Languages

Python, JavaScript, Java, C++, Rust, Go, TypeScript, C#, and many more. All compilers and interpreters in one place. Switch languages instantly.

Dark & Light Mode

Switch between light and dark themes with one click. Code comfortably in any lighting condition, day or night.

Mobile Friendly

Fully responsive editor optimized for phones, tablets, and Chromebooks. Code on any device with a web browser. No app download needed.

Save & Share Code

Save programs to your account, share via unique URLs, and let others view, fork, and run your code. Great for collaboration and code reviews.

Tags & Organization

Organize your saved programs with tags and find them quickly with search and filters. Build a personal library of code snippets and solutions.

No Account Required

Start writing and running code immediately. No sign-up, no email, no credit card. Create a free account later only if you want to save your work.

Explore more programming languages

myCompiler supports 27+ languages. Switch between them anytime. All free, all in one place.

View all 27+ languages

Frequently asked questions

Common questions about using the online Kotlin compiler, playground, and code runner.

Yes! myCompiler is completely free for all supported languages including Kotlin. There are no subscriptions, no premium tiers, and no hidden costs. Every feature is available at no charge.

myCompiler keeps its Kotlin environment up to date. You can see the exact version on the language details section of this page. We regularly update all language runtimes to their latest stable versions.

myCompiler runs Kotlin on the JVM, so you can practice Kotlin syntax, algorithms, and core language features. While Android-specific APIs are not available, it is perfect for learning Kotlin fundamentals.

Simply open the Kotlin editor, write or paste your code, and click the Run button. Your code will be executed on our servers and the output will appear in the terminal panel within seconds.

Yes. Click Save to store your program. You will receive a unique URL that you can share with anyone. Recipients can view, fork, and run your code.

Yes. myCompiler supports multi-file projects. You can create, rename, and delete files in the sidebar. This lets you organize your Kotlin code just like in a local IDE.

Yes. All code runs in isolated containers on our servers. Each execution gets its own sandboxed environment that is destroyed after completion. Your code cannot affect other users or our infrastructure.

Yes. myCompiler has a responsive design optimized for phones and tablets. You can write and run Kotlin code on the go. The mobile interface uses tabs for switching between the editor, output, and file panels.

Yes. Click the Input tab in the bottom panel, type or paste your input data, then click Run. Your program will read from the input you provided.

Execution is fast. Code runs on our optimized cloud infrastructure and output typically appears within seconds. Execution time depends on the complexity of your program.

Yes. myCompiler provides an embed feature. You can copy an iframe snippet and paste it into your website, blog, or documentation. Visitors can edit and run code directly on your page.

myCompiler supports common editor shortcuts including Run (Ctrl/Cmd+Enter), Save (Ctrl/Cmd+S), Find (Ctrl/Cmd+F), and more. See the keyboard shortcuts section on this page for the full list.

No. myCompiler requires an internet connection because code is compiled and executed on our cloud servers. The editor itself loads in your browser, but running code requires connectivity.

myCompiler offers a fast, free, zero-setup environment with a modern code editor, multi-file support, dark mode, and instant sharing. It is ideal for learning, prototyping, interviews, and sharing code examples.

Yes. myCompiler is great for practicing algorithms and coding problems. You can write Kotlin code, provide custom input, and test your solutions instantly. Save your work and come back to it anytime.

Use print statements or console output to trace your program's behavior. myCompiler shows all standard output and error messages in the terminal panel. Error messages include line numbers to help you locate issues.

Ready to write Kotlin code?

Open the free Kotlin playground and start coding immediately. No downloads, no account required.

Start coding in Kotlin

Free · No sign-up required · Kotlin 2.2.10