Kotlin Online Compiler

Write, compile, and run Kotlin code online for free. Use custom standard input and view program output without installing the Kotlin compiler and JVM.

Run the program
Output
Run Kotlin Code Online
This free Kotlin online compiler runs a single source file named Main.kt in an isolated execution environment. Edit the starter program, provide optional input, and select Run to see standard output and compiler errors.
How to Use the Kotlin Compiler
  1. Write or paste a complete Kotlin program in the code editor.
  2. Add input in the Input tab when the program reads from standard input.
  3. Select Run. Compilation errors, runtime errors, and program output appear in the Output panel.
Kotlin Execution Notes
The Kotlin source is compiled into a JVM application before execution. A top-level main function is supported.
Programs can read values using readln, readLine, or System.in. Execution time, memory, processes, output size, and network access are limited to keep the shared compiler responsive and secure.
Frequently Asked Questions
Do I need to install Kotlin?
No. Compilation and execution happen remotely, so the editor works from a modern browser on desktop or mobile.
Can I provide input to my program?
Yes. Enter one or more lines in the Input tab before selecting Run. The text is passed to the program through standard input.
Continue learning with the Kotlin tutorials and examples.