Code Playground

Write, run, and debug code with multi-language support. Includes JS/TS with Node.js runtime (require, process, Buffer, fs, path, crypto, events), Python runtime, HTML/Markdown preview, SQL support, formatting, and linting.

JAVASCRIPT Editor

Console Output

Run your code to see output here

Overview

Write and Execute Code in Six Languages Without Leaving Your Browser

The Code Playground gives you a full Monaco editor (the same engine behind VS Code) paired with a live execution environment that supports JavaScript, TypeScript, Python, HTML, Markdown, and SQL — all running locally in the browser, with no backend or installation required. JavaScript and TypeScript run with a complete Node.js-compatible runtime that polyfills require(), process, Buffer, fs, path, os, crypto, events, http, and more, so common Node.js patterns work without modification.

Python execution is powered by Pyodide (a real CPython interpreter compiled to WebAssembly), HTML and Markdown render in a live preview pane that updates as you type, and SQL runs through alasql with full CREATE TABLE, INSERT, and SELECT support. TypeScript is transpiled on the fly via Babel standalone before execution, and a Prettier-backed format button keeps your code clean.

100% freeNo sign-upNode.js runtime includedPython, HTML, SQL, Markdown

How to use it

1Pick a language from the selector in the editor toolbar — JavaScript, TypeScript, Python, HTML, Markdown, or SQL — and the editor loads a starter template for that language.
2Write or paste your code; IntelliSense, syntax highlighting, and Node.js type declarations are active for JavaScript and TypeScript.
3Click Run (or press the run shortcut) to execute the code. Output appears in the right-hand panel; runtime errors are highlighted separately.
4Use Format to auto-format the current file with Prettier, or Lint to run a syntax check and receive warning messages.
5Save the file to disk with the Save button or load an existing file from your device; the language is detected automatically from the file extension.

Key features

Monaco editor with full IntelliSense, bracket matching, multi-cursor support, and configurable font size.

Node.js runtime polyfill covering require(), process, Buffer, fs (in-memory), path, os, util, events, assert, crypto, url, querystring, http, https, stream, buffer, and timers.

Real Python execution via Pyodide (CPython compiled to WebAssembly) with stdout and stderr capture.

HTML and Markdown live preview that updates automatically as you edit, rendered in a sandboxed iframe.

SQL execution via alasql supporting DDL and DML statements with JSON result display.

Prettier-powered code formatting for JavaScript, TypeScript, HTML, CSS, and Markdown.

Draggable divider between editor and output panels, with per-panel maximize buttons for focused work.

Frequently asked questions

Can I use npm packages in the JavaScript playground?

Only Node.js built-in modules are available via require(). Third-party npm packages are not resolvable because there is no network module loader in the browser sandbox.

How does Python execution work?

Python runs through Pyodide, which is CPython compiled to WebAssembly. The runtime is downloaded from a CDN on first use and then cached by the browser. Most standard library modules are available.

Is my code sent to any server?

No. All execution happens locally in your browser tab. Code is not uploaded to sourcecodestack or any third party.

Does TypeScript type-checking work?

Yes. The Monaco editor runs the TypeScript language service in the browser, providing type errors and IntelliSense. At runtime, Babel strips the type annotations before executing the resulting JavaScript.

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Full Guide Available

Code Playground Complete Guide

Learn how to run HTML/CSS/JS live, share snippets, and prototype ideas in your browser.

What's inside

Run HTML, CSS & JS live

Build & share code snippets

Common questions answered

Read Full Guide

Code Playground

JAVASCRIPT Editor

Console Output

Write and Execute Code in Six Languages Without Leaving Your Browser

How to use it

Key features

Frequently asked questions

Code Playground Complete Guide

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