What is HTML Editor?

This is a full-featured online HTML editor with real-time preview. Write or paste HTML code in the left panel and instantly see the rendered result on the right. It combines a syntax-highlighted code editor with a sandboxed preview pane, so you can build and iterate on web pages without leaving your browser.

Unlike a simple viewer, this editor is designed for writing and editing. Upload existing HTML files, format messy code with one click, and download your finished work. The HTML standard is maintained by the <a href="https://html.spec.whatwg.org/multipage/" target="_blank" rel="noopener">WHATWG</a>, and this tool supports all modern HTML5 features.

Everything runs locally in your browser. Your HTML code never touches our servers. It's fast, free, and completely private.

How to Use the HTML Editor

Follow these steps to write, edit and preview your HTML. Every feature is available from the toolbar buttons above the editor.

Write or Upload HTML

Start typing HTML in the editor, or click Upload to load an existing .html file from your computer. You can also click Sample to load a demo page. For valid HTML structure, check the web.dev HTML guide.

See the Live Preview

The right panel renders your HTML instantly as you type. CSS styles, images, and even JavaScript execute within the sandboxed iframe preview.

Format and Edit

Click Format to auto-indent your code for readability. Drag the splitter to resize the editor and preview panels. Click Maximize to view the preview in fullscreen.

Download or Copy

Click Download to save your work as an .html file, or Copy to copy the code to your clipboard. Validate your output with the W3C Markup Validator before publishing.

When You'd Actually Use This

Prototyping Web Pages

Quickly build and test HTML layouts, components, or entire pages. See your changes render in real time without setting up a local development environment.

Learning HTML

Perfect for beginners learning HTML. Write tags, see what they do, experiment with attributes and styles. The instant feedback loop makes learning much faster than the traditional write-save-refresh cycle.

Testing Code Snippets

Got an HTML snippet from a tutorial, Stack Overflow answer, or documentation? Paste it in, see how it renders, tweak it, and copy the result. Great for quick experiments.

Email Template Editing

Email HTML is notoriously tricky with inline styles and table layouts. Upload your email template, edit it visually, and download the result. Faster than editing raw HTML in a text editor.

Common Questions

Is my HTML data stored anywhere?

No. Everything runs entirely in your browser using JavaScript. Your HTML never leaves your computer unless you explicitly download or copy it.

Does the editor support CSS and JavaScript?

Yes. Inline styles, <style> tags, and <script> tags all work. External stylesheets and scripts referenced via URLs will also load if they're accessible. The preview runs in a sandboxed iframe for security.

What file formats can I upload?

You can upload .html and .htm files. The content will be loaded directly into the editor.

How does the Format button work?

The Format button auto-indents your HTML code with proper nesting. It makes messy or minified HTML readable without changing the rendered output.

Can I use this as an HTML playground?

Absolutely. It works great as a sandbox for experimenting with HTML, CSS, and JavaScript. Write code, see the result instantly, iterate quickly.

Is the preview safe to use with untrusted HTML?

The preview renders inside a sandboxed iframe, which isolates it from the main page. However, if you're working with completely untrusted HTML, review the code before running scripts.

Related HTML & Web Tools

This editor is great for writing and previewing HTML, but sometimes you need complementary tools: