Experiment. Break things. Learn.

Your coding playground.

A safe space for learners to run real JavaScript. Your curiosity is the only prerequisite.

Language

Sample exercise

hello.js

Editable code

// Your first JavaScript program
console.log("Hello, Mycode!");

Draft kept on this device when saved

Console output

Press Run code to see what your program does. Syntax and runtime errors will appear here too.

Output test cases

Send a greeting to the console. Try changing the text, then run it again. Tests compare each console line with the expected value; they do not prove correctness for every input.

Prints the greeting

JavaScript runs in a dedicated worker inside an origin-isolated iframe, not on this page. Network access is blocked and execution stops after two seconds. Browser DOM APIs are not available.