HTML Viewer

About the HTML Viewer Tool

What is an HTML Viewer?

An HTML viewer takes the HTML you paste in and shows you the rendered page next to it, so you can see what your markup actually produces instead of reading angle brackets. Type or paste a snippet, drop in a whole file, and the preview updates as you go — CSS in your style tags styles it, JavaScript in your script tags runs, and the viewport buttons let you check how it looks on a phone or tablet.

None of that touches a server. The page renders your code in your own browser, inside a locked-down sandbox iframe, so scripts and forms run without ever reaching your real cookies or session. That makes it a safe place to try a snippet you found online, test an embed code, or debug a layout you can't figure out — nothing you paste is uploaded or logged.

The viewer also gives you the two things you'd normally open DevTools for: a console panel under the preview that captures console.log output and JavaScript errors from your snippet, and a Share Preview button that packs your code into a link you can send to anyone — no account, no upload, the code travels inside the URL itself.

How to Use This Tool

1. Step 1: Input your code. Type your HTML directly into the editor, paste existing code, or drag and drop an .html file straight onto it. The small toolbar above the editor can also open a file from your computer, fetch a page's source by URL, or load a ready-made sample. CSS goes inside style tags, and JavaScript fits into script tags.
2. Step 2: View the live preview. Look at the pane below the editor to see your rendered webpage. Keep the "Auto-update Preview" box checked if you want to see visual changes as you type. Alternatively, uncheck it and click "View/Run HTML" to refresh the screen manually. Any console.log output or script errors show up in the console panel under the preview.
3. Step 3: Test responsive designs. Check how your layout looks on different screens. Click the Mobile, Tablet, or Desktop icons above the preview area to resize the iframe and verify your media queries. On a wide monitor, the split-view button puts the editor and preview side by side.
4. Step 4: Save and share your work. When you finish testing, use the copy or download icons in the editor toolbar to keep the code, or hit "Share Preview" to copy a link that opens your exact snippet for anyone. The trash icon clears everything so you can start over.

Common Use Cases

A scratch pad that renders instantly turns out to be useful more often than you'd expect. Here's what people reach for it to do:

• Debugging HTML and CSS: Find out exactly why a layout breaks. Paste the problematic markup here to see if the error comes from the code itself or from conflicting styles in your main project files.
• Prototyping UI Components: Test new buttons, menus, or cards in isolation. You can tweak CSS properties and see the visual updates immediately.
• Checking Responsive Layouts: Verify how Flexbox or CSS Grid structures adapt to smaller screens. The viewport icons make it easy to simulate mobile and tablet devices.
• Testing JavaScript Logic: Write small scripts to manipulate DOM elements or test event listeners. The sandboxed iframe runs vanilla JavaScript safely.
• Building Email Templates: Email clients require strict HTML table structures and inline styles. A blank viewer helps you test these layouts before sending them to a campaign manager.
• Validating Embed Codes: Paste third-party tracking scripts, video iframes, or social media widgets to ensure they load correctly without disrupting the rest of your page.
• Refactoring Legacy Code: Clean up old, bloated markup. You can remove outdated tags and update CSS classes while checking the live output to make sure the design stays intact.
• Learning Web Design: Beginners can practice writing code and see the instant results of combining HTML tags, CSS rules, and JavaScript functions.

The viewer pairs well with the rest of our HTML toolbox: run messy markup through the HTML Formatter to clean up the indentation, check it for unclosed tags and duplicate ids with the HTML Validator, compress the final version with the HTML Minifier, or diff two versions of a page in the HTML Compare tool.

Frequently Asked Questions

Will it run my JavaScript?

Yes. Any JavaScript you put inside standard script tags will run directly in the preview window. We sandbox the iframe to protect your main browser session, but standard DOM manipulation works perfectly fine.

Can I link to external CSS or JS files?

You can definitely include external stylesheets and scripts using standard link and script source tags. Just keep in mind that your browser still enforces strict CORS (Cross-Origin Resource Sharing) rules. If the host server blocks cross-origin requests, the external file simply won't load in the preview.

How do the mobile and tablet views work?

When you click the device icons, the preview pane locks to common viewport widths. For example, the mobile view snaps to a standard 375px width. This gives you a fast way to test CSS media queries without constantly resizing your browser window.

Is my code saved on your servers?

Absolutely not. The rendering process happens 100% locally in your own browser. We never track, store, or transmit your code to our servers.

Do I have to include the standard HTML document tags?

Not for simple tests. Modern browsers know how to render a stray div or button even if the base document structure is missing. But if you plan to test specific meta tags or page-level CSS, you should probably include the full HTML boilerplate.

Can I load frameworks like Tailwind or Bootstrap?

Yes, that works perfectly. Just grab the CDN link for whatever framework you want to use and paste it at the top of your code. For Tailwind, you can use their Play CDN script tag to get instant utility classes.

Can I see console.log output and JavaScript errors?

Yes. The console panel under the preview captures console.log, warnings, errors, and even uncaught exceptions with their line numbers, so you can debug scripts without opening DevTools. If you want a completely untouched render, flip the Console switch off.

How do share links work? Is my code uploaded somewhere?

No upload happens. Share Preview compresses your code with your browser's built-in compression and packs it into the link after the # symbol. That fragment is never sent to any server — whoever opens the link has the code decompressed right in their own browser.

What is a good HTML viewer?

A good HTML viewer renders your code the instant you type it, runs JavaScript in a safely sandboxed frame, lets you test mobile and tablet widths, and shows console output so you can actually debug — all without uploading your code anywhere. Those are exactly the boxes this tool was built to tick, and it's free with no sign-up.

How do I open HTML files without a viewer?

Just double-click the file — your default browser will render it from your own disk. To see or edit the code instead, right-click it and open it with any text editor, like Notepad or VS Code. What a local file can't give you is the edit-and-see loop: with a viewer you change the code and watch the result update without saving and refreshing anything.

How do I open an HTML viewer in Chrome?

Chrome doesn't ship an editor with a live preview built in. You can drag an .html file into a tab to render it, press Ctrl+U to read a page's source, or open DevTools with F12 — but for writing code and watching it render side by side, a browser-based viewer like this page is the quickest route. It runs entirely inside Chrome (or any modern browser) with nothing to install.