Kotlin Online Compiler
Write, compile, and run Kotlin code online directly from your browser with our free Online Kotlin Compiler. Test Kotlin syntax, functions, classes, collections, and JVM-based programming concepts without installing the Kotlin SDK, Android Studio, IntelliJ IDEA, or configuring a local development environment.
How to Use This Kotlin Compiler
- Write or paste your Kotlin code
Enter your program in the Code Editor. You can test variables, functions, loops, classes, collections, null-safety features, and other standard Kotlin syntax supported by the execution environment. - Click the Run button
Select Run to compile and execute your Kotlin program. If your code contains a compilation or runtime error, review the returned message, correct the relevant code, and run it again. - Check the Output screen
Your program result appears in the Output panel. Use the available controls to copy, download, or delete the output before testing another program.
Key Features
- Free Online Kotlin Compiler: Write and execute Kotlin programs directly from a modern web browser.
- Zero Installation: No need to install the Kotlin compiler, JDK, Android Studio, or IntelliJ IDEA for supported programs.
- Instant Execution: Click Run and quickly view your program output or compiler feedback.
- Standard Kotlin Syntax: Practice functions, classes, objects, collections, loops, conditions, lambdas, extension functions, and other core language features.
- Null Safety Support: Experiment with nullable types, safe calls (
?.), the Elvis operator (?:), and other Kotlin null-safety concepts. - JVM-Based Execution: Test standard Kotlin/JVM code and supported Java interoperability features available in the configured runtime.
- Dark and Light Mode: Switch the Code Editor theme for comfortable coding in different lighting conditions.
- Output Controls: Copy, download, or clear generated output directly from the Output panel.
1. How do I print output in this Kotlin compiler using println()?
Kotlin provides the built-in println() function for displaying text and values.
Enter the code in the Code Editor, click Run, and view the result in the Output screen.
You can also use string templates:
2. Do I need to install Java or the Kotlin SDK to use this compiler?
No. You can use this Online Kotlin Compiler directly from your browser without installing the Kotlin SDK, JDK, Android Studio, or IntelliJ IDEA for supported Kotlin programs.
A local development setup may still be preferable for large applications, Gradle projects, external dependencies, debugging, or full Android development.
3. Can I test Android-specific Kotlin code here?
This compiler is intended primarily for standard Kotlin/JVM code, not complete Android applications.
You can practice Kotlin syntax and business logic, but Android-specific APIs such as Activity, Context, View, Jetpack Compose components, or other Android framework classes usually require the Android SDK and an Android project environment such as Android Studio.
4. Can I use Kotlin collections and standard library functions?
Yes, commonly available Kotlin standard-library features can be used when supported by the configured runtime.