Write, compile, and run JavaScript code online for free in the Mentrily playground. No setup required.
Run code instantly in the Mentrily playground.
The Mentrily online JavaScript compiler lets you write, compile, and run JavaScript code directly in your browser. Your program executes in a secure cloud sandbox with standard input support, so it behaves the same way it would in a local terminal — without installing a compiler, IDE, or toolchain.
It is perfect for practicing JavaScript, testing snippets, preparing for coding interviews, and classroom use. Start typing and hit Run — no account required.
Yes. The Mentrily JavaScript compiler is completely free. You can write, compile, and run JavaScript code online without creating an account or installing anything.
No. Your JavaScript code is compiled and executed in a secure cloud sandbox, so it works on any device with a browser — laptops, Chromebooks, and tablets included.
Yes. The playground supports standard input, so programs that read from stdin work the same way they would in a local terminal.
Yes. Create a free Mentrily account to keep your work, or use the built-in question builder to turn a snippet into a shareable practice problem.
Yes. Mentrily is a full teaching platform — educators can build courses and proctored exams with auto-graded JavaScript coding questions, then track learner progress in one dashboard.
Mentrily supports 30+ languages. Jump straight into another playground: