Where does my code run?

In a sandboxed iframe inside your own browser. It has no access to this page, your cookies or any server.

Is TypeScript type-checked?

The code is transpiled and syntax errors are reported. Full type checking is not run, so type-only mistakes still execute.

Can I use await at the top level?

Yes. Your code is wrapped in an async function, so top-level await works.

What happens with an infinite loop?

The run is aborted at the timeout you set (4 seconds by default) and the console shows a timeout error.

Can I import npm packages?

No. The sandbox has no bundler or network module resolution — paste self-contained code instead.

JavaScript / TypeScript Playground

Write and run JavaScript or TypeScript with a live console.

Works Offline

Privacy First

No Login

No API

iframe sandbox

postMessage

TypeScript editor

Language

Timeout (ms)

Auto-run

Top-level await is supported. Code runs in a sandboxed iframe with no access to this page, your cookies or the network origin.

Console

Run your code to see console output here.

About the JavaScript / TypeScript Playground

A browser-based editor that runs JavaScript or TypeScript instantly. TypeScript is transpiled locally, then the code executes inside a sandboxed iframe with console.log, warn, error and table captured into a timestamped console. Supports top-level await, an execution timeout for runaway loops, auto-run, and a view of the compiled JavaScript.

Examples

TypeScript snippet

const n: number = 40 + 2; console.log(n);

Output

LOG 42

Keyboard shortcuts

Copy the main outputCtrl / ⌘ + Shift + C
Download the resultCtrl / ⌘ + S
Share this toolCtrl / ⌘ + Shift + S
Reset the inputsAlt + R
Open the tool search paletteCtrl / ⌘ + K

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-17 · Runs entirely in your browser