Is it safe to preview untrusted HTML here?

The preview renders inside a sandboxed iframe, which restricts what embedded content can do. Still, treat unknown HTML with the same caution you would anywhere.

Why does my email template look different in real clients?

Email clients (especially Outlook) use rendering engines far more limited than a browser. A browser preview catches structural errors, but always send test emails for final verification.

Does the preview execute JavaScript?

Scripts are constrained by the iframe sandbox. The tool is designed for checking markup and styling rather than running interactive applications.

Can I preview a full page with external CSS?

Inline styles and embedded blocks render directly. External stylesheets load only if their URLs are absolute and reachable from your browser.

HTML Viewer | Hexabench

HTML Source

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <style>
    body { font-family: system-ui, sans-serif; padding: 2rem; max-width: 600px; margin: 0 auto; }
    h1 { color: #2563eb; }
    .card { border: 1px solid #e2e8f0; border-radius: 8px; padding: 1.5rem; margin: 1rem 0; }
    button { background: #2563eb; color: white; border: none; padding: 0.5rem 1.25rem; border-radius: 6px; cursor: pointer; }
    table { width: 100%; border-collapse: collapse; }
    th, td { padding: 0.5rem 0.75rem; border: 1px solid #e2e8f0; text-align: left; }
    th { background: #f8fafc; }
  </style>
</head>
<body>
  <h1>Hello, Hexabench!</h1>
  <p>This is a live HTML preview. Edit the code on the left to see changes instantly.</p>
  <div class="card">
    <h2>Sample Card</h2>
    <p>A styled component using plain CSS.</p>
    <button onclick="alert('Clicked!')">Click Me</button>
  </div>
  <table>
    <tr><th>Name</th><th>Role</th><th>Status</th></tr>
    <tr><td>Alice</td><td>Engineer</td><td>Active</td></tr>
    <tr><td>Bob</td><td>Designer</td><td>Active</td></tr>
  </table>
</body>
</html>

Preview

Preview HTML online in a sandboxed viewer

Paste raw HTML and see it rendered instantly inside a sandboxed iframe, with a light/dark toggle. Ideal for checking email templates, CMS fragments, and snippets without creating a file or risking script execution in your page.

Frequently Asked Questions

Is it safe to preview untrusted HTML here?: The preview renders inside a sandboxed iframe, which restricts what embedded content can do. Still, treat unknown HTML with the same caution you would anywhere.
Why does my email template look different in real clients?: Email clients (especially Outlook) use rendering engines far more limited than a browser. A browser preview catches structural errors, but always send test emails for final verification.
Does the preview execute JavaScript?: Scripts are constrained by the iframe sandbox. The tool is designed for checking markup and styling rather than running interactive applications.
Can I preview a full page with external CSS?: Inline styles and embedded <style> blocks render directly. External stylesheets load only if their URLs are absolute and reachable from your browser.

Preview HTML online in a sandboxed viewer

Frequently Asked Questions

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