In the browser

Online Compiler

Free online compiler for JavaScript, Python, HTML and CSS. Run code in the browser — no install, no sign-in.

JavaScript
Ctrl + Enter to run Auto-saves your last code in this browser
Output 
Ready. Pick a language and hit Run.

Practice

Quick challenges

4 tasks

JavaScript Easy

Sum two numbers

Add 7 and 5 and print the sum.

Open in compiler
Python Easy

FizzBuzz

Print 1–20 with FizzBuzz rules.

Open in compiler
JavaScript Medium

Palindrome check

Check if a string is a palindrome.

Open in compiler
HTML Easy

Styled card

Build a small card with HTML + CSS.

Open in compiler

Online compiler questions

Is the Codementrix online compiler free?

Yes. JavaScript, Python, HTML and CSS run in your browser. You do not need an account.

Which languages can I run online?

JavaScript, Python, HTML and CSS. Code runs locally in the browser.

Do I need to install a compiler?

No. Open the page and run code in the editor. Nothing is installed on your computer.