HTML Viewer

Type or paste HTML — with optional CSS and JavaScript — and see it rendered instantly in a safe, sandboxed preview. Switch between desktop and phone widths, or use tab view to keep your code and the live result side by side.

Your code is rendered inside a sandboxed frame in your own browser and never uploaded.

How to use HTML Viewer

  1. Paste your HTML into the code box (CSS and JS have their own tabs).
  2. The preview renders automatically as you type.
  3. Use the device buttons to switch between desktop and mobile width.
  4. Use the layout tabs for code only, preview only, or both side by side.
  5. Open the result in a new tab, or copy and download your code.

About this tool

Browsers cannot show you what an HTML snippet looks like until you save it as a file and open it. The HTML Viewer removes that round-trip: your markup is rendered immediately in a sandboxed frame, which is perfect for testing snippets, email templates, homework exercises and code from tutorials.

Desktop view shows the full layout, mobile view renders at phone width so you can check responsiveness, and tab view keeps the code and the live preview side by side so every change is visible the moment you make it.

When to use it: testing snippets, homework, email templates and tutorial code without saving files.

Frequently asked questions

Is my code uploaded anywhere?
No. The preview is rendered entirely inside your browser using a sandboxed frame. Nothing is sent to any server.
Can I include CSS and JavaScript?
Yes. Separate tabs hold your CSS and JS, and they are combined with the HTML in the preview, just like a real page.
Why can’t the preview navigate to other websites?
The sandbox intentionally blocks navigation and third-party popups, so testing unknown code stays safe.
Can I use it to test email templates?
Yes — paste the template’s HTML and check it at desktop and mobile widths. Remember that email clients render differently from browsers, so also test in the actual client before sending.
What is the mobile view width?
About 390 pixels — the width of a typical modern phone — so you can judge how a layout behaves on small screens.
Is it a replacement for a code editor?
It is a previewer, not an editor project: perfect for snippets, exercises and quick tests, while real projects still belong in an editor or IDE.

Related tools

Markdown Previewer Write Markdown on the left and see the formatted result instantly. CSS Minifier Compress CSS by removing comments and unnecessary whitespace. HTML Entity Encoder Encode or decode HTML entities like &, < and ©. JSON Formatter Format, indent and beautify JSON data so it is easy to read.

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How to use Html Viewer

Paste your code, data, or URL into the Html Viewer input area. Select the appropriate mode or option, then process. The formatted or converted output appears clearly and can be copied or saved.

Practical benefits

Frequently asked questions

Is this tool free to use?
Yes. Html Viewer is fully free with no account or subscription required.
Does it upload my files?
No. All processing occurs locally within your browser session.
Can I use this for professional projects?
Yes, the tool is designed for both casual and professional use. Always verify critical outputs.