HTML Viewer
Paste HTML and see a live, sandboxed preview of how it renders.
Scripts are disabled in the preview for safety — only markup and styling are rendered.
What is HTML Viewer?
An HTML viewer renders pasted markup exactly as a browser would, without needing to save it as a file and open it, or spin up a local server. Paste a full document or just a fragment, and you get an instant, live-updating preview alongside your source — useful for checking how an email template, a widget snippet someone handed you, or a piece of markup you're debugging actually looks before you commit to using it. The preview runs inside a sandboxed iframe with scripting disabled, so pasted HTML can render its structure and styling safely without ever being able to run JavaScript against this page.
How to Use HTML Viewer
- Paste your HTML into the source box — a full document or just a fragment both work.
- The rendered preview updates live on the other side as you type.
- If your fragment doesn't include its own <html> wrapper, one is added automatically behind the scenes so it still previews correctly.
- Scripts never execute in the preview, by design — see the FAQ for why.
Examples
Bare fragment
Input: <p>Hello <strong>world</strong></p>
Output: Renders as a paragraph with "world" in bold, wrapped in a minimal document automatically.
Full document
Input: <html><head><style>p{color:blue}</style></head><body><p>Styled text</p></body></html>
Output: Renders with the blue text color applied, exactly as a browser would.
Common Mistakes
- Pasting a snippet that relies on a <script> to render its content (e.g. a client-side templating widget) and expecting to see the final output — since scripts don't run, only the static markup you actually typed will show.
- Using relative image/asset paths (like "images/logo.png") and expecting them to resolve — the preview has no real page URL to resolve relative paths against, so use absolute URLs when previewing.
- Assuming a blank preview means broken HTML — an empty result is more often a missing closing tag hiding the rest of your content than a hard error, since the preview is tolerant like a real browser is.
- Expecting form submissions or interactive JS-driven behavior to work in the preview — sandbox restrictions specifically block that.
Why Use This Tool
- Instant, live preview with no file saving or local server required.
- Safe by construction — the sandboxed iframe cannot execute scripts against this page, regardless of what you paste.
- Works with both bare fragments and full HTML documents.
- Runs entirely client-side — nothing you paste is sent to a server.