Real Time HTML Editor

Unsupported input

The tool may reject input that does not match the expected content, structure, or file type.

Fix: Confirm the tool input requirements and paste the correct type of data.

Incomplete values

Missing fields or partial content can block processing or produce weak results.

Fix: Provide the full required input before running the tool.

Copying placeholder content

Sample or placeholder values can lead to output that looks valid but is not ready for real use.

Fix: Replace placeholders with your actual values before relying on the result.

How does the editor compare to CodePen or JSFiddle?

This editor is single-file, client-only, and privacy-preserving — nothing is stored on our servers, so there's no login, no pen history, and no rate limits. It's ideal for quick prototyping and teaching. For collaborative pens, a preview gallery, or persistent portfolios, CodePen is a better fit. For bugs that need a reproducible URL, JSFiddle or CodePen's 'share' works just like ours.

Is pasted JavaScript safe to run?

The preview iframe uses sandbox='allow-scripts' without allow-same-origin, which means scripts run but can't access your cookies, localStorage, or any cross-origin resource from this domain. That's enough isolation to safely test an unknown snippet, though it's not a substitute for reading the code if you're worried about exfiltration to an external URL.

Does the editor support external resources (fonts, CDN libraries)?

Yes — add <link> and <script> tags to the HTML pane like you would in any page. jQuery, React, Tailwind CDN, Google Fonts, and anything served with CORS open all work. Anything blocked by CORS or CSP on the remote host won't load, same as in any browser.

Is my code saved anywhere?

Not on our servers. The editor state is stored only in your browser's localStorage for the current tab. Sharing generates a URL with the state encoded in the fragment (#…) — fragments are never sent to our server, so even sharing doesn't leak to us. Clearing your browser data wipes your work.

Can I import files instead of pasting?

Yes — drag any .html, .css, or .js file onto the corresponding tab and its contents load directly. For multi-file projects, paste the files one per tab or inline them with <script> and <style>; for anything bigger, a real dev server (Vite, Next.js) is the right tool, not a single-file playground.

Why does my preview flicker or reset every time I type?

By default, every change reloads the iframe to ensure side-effect-free rendering. If you're running a timer, animation, or WebSocket that shouldn't restart on every keystroke, increase the debounce to 1000 ms or higher in Settings. For animation-heavy work, toggle 'manual refresh' and rerun the preview with Cmd/Ctrl+Enter only when you're ready.