The AllTools Code Playground is a free, browser-based HTML, CSS, and JavaScript live editor. It gives you a split-panel workspace: a tabbed code editor on the left and a sandboxed live preview iframe on the right. Every keystroke updates the preview in real time, with a 300ms debounce to keep things smooth.

Unlike heavyweight online IDEs that require accounts, subscriptions, or server-side execution, the Code Playground runs entirely in your browser. Your code is executed locally using a sandboxed <iframe> with the srcdoc attribute — your code never leaves your machine, and the preview is generated instantly without any network round-trip.

The editor supports Tab key indentation (2 spaces by default), live line numbers that sync with your scroll position, and auto-save to localStorage every 2 seconds so your work is never lost even if you accidentally close the tab.

The FORMAT button applies basic auto-indentation to your HTML, CSS, and JavaScript code, making messy code easier to read. The COPY HTML button exports the complete combined document (HTML + embedded CSS + embedded JS) to your clipboard as a single self-contained HTML file you can save and share.

The FULLSCREEN button expands the preview panel to fill the entire viewport — useful for testing responsive layouts at different screen sizes or presenting your work. Press Escape or click Fullscreen again to return to the split view.

The Code Playground is ideal for quickly prototyping a UI component, testing a CSS animation, experimenting with a JavaScript algorithm, learning HTML and CSS fundamentals, or preparing a code demonstration. It is a focused, distraction-free coding environment that requires zero setup. Open the page and start coding immediately.