A JavaScript and TypeScript playground that runs in your tab

Need to check how a function behaves, test a regex or try a TypeScript type? The JS/TS Playground runs your code right in the browser, with no Node.js, project setup or bundler.

What you get

• Write JavaScript or TypeScript in a syntax-highlighted editor with line numbers and bracket matching.
• TypeScript is converted to JavaScript in your browser before it runs.
• console.log, warnings and errors appear in the output panel.
• Format tidies messy code in one click.
• Fullscreen gives the editor and output the whole screen.

Good uses

• Try array methods like map, filter and reduce on sample data.
• Check date, number and string formatting before putting it in an app.
• Test async code with Promises and await.
• Sketch TypeScript interfaces, then generate them from real data with JSON to TypeScript.
• Debug patterns in the Regex Tester, then use them in code here.

Need a web page instead?

If your code changes HTML or CSS, use HTML Live Preview, which shows the page as you type.

Limits to know

• Code runs in a browser, so Node-only modules such as fs and child_process are not available.
• Network requests follow normal browser rules, so some sites block them.

Private by default

Nothing you write is uploaded. For Python, the Python Playground works the same way.