Code Playground — Write & Run Code Online
An in-browser IDE to write and run JavaScript, Python, or HTML/CSS/JS instantly, with live console output and preview — no setup, nothing installed.
- Pick JavaScript or Python for a console-style runner, or HTML/CSS/JS for a full live-preview page.
- Write or paste your code into the editor pane.
- Click Run to execute it instantly inside a sandboxed iframe — nothing leaves your browser. Python's runtime loads on first run.
- View console/print output or the rendered preview on the right, then copy your code when you're done.
All processing happens entirely in your browser. Your data never leaves your device.
Key Features
- JavaScript execution with full console output and error reporting
- Python 3 runtime via Pyodide WebAssembly — runs entirely in the browser
- HTML/CSS/JS mode with a live side-by-side preview panel
- Syntax highlighting and code formatting powered by Monaco Editor
- Sandboxed execution — your code never leaves your device
- One-click copy to share your snippet elsewhere
About Code Playground
A code playground (also called an online IDE or sandbox) is a browser-based environment that lets you write, execute, and debug code without installing compilers, runtimes, or editors on your machine. It is widely used by developers for quick prototyping, testing snippets, learning new languages, and sharing runnable examples with colleagues.
ForgeKit's Code Playground supports JavaScript, Python, and a combined HTML/CSS/JS mode with a live preview panel. Every execution is sandboxed inside your browser using iframes and Web Workers, meaning your source code and output never leave your device. Python is powered by Pyodide, a WebAssembly port of CPython, so the full standard library is available without a server round-trip.
Whether you're debugging a tricky algorithm, experimenting with a new API, or teaching a friend how to code, the playground provides instant feedback with zero friction — no accounts, no downloads, no latency.
Frequently Asked Questions
No. All code executes entirely inside your browser using sandboxed iframes and WebAssembly. Nothing is uploaded or stored on any server.
It uses CPython 3.x compiled to WebAssembly via Pyodide. The full standard library is available, though native C extensions that aren't ported to WASM are not supported.
JavaScript runs in a vanilla browser environment, so browser-native APIs are available but npm packages are not. For Python, many pure-Python pip packages can be installed via Pyodide's micropip.
There is no hard time limit, but infinite loops will freeze your browser tab. The playground includes a basic watchdog that warns you if a script appears unresponsive.
You can copy your code to the clipboard and paste it into any file. Persistent saving to the server is not offered because ForgeKit is a privacy-first, no-account platform.