Sandboxed HTML preview

0 uploads — runs entirely in your browser, works offline

Sandboxed HTML preview — safely render HTML

Paste HTML and see it rendered inside an isolated sandbox. It runs entirely in your browser (0 uploads, works offline).

How to use it

  1. Paste your HTML.
  2. See it rendered in a locked-down iframe.
  3. Iterate safely.

FAQ

How do I preview HTML safely for free?

Paste the HTML and this page renders it inside an iframe with a strict sandbox — scripts can run but cannot read cookies, storage or this page — on your device with no upload.

Why is a sandbox important?

Untrusted HTML can carry scripts that try to steal data or hijack the page. The sandbox isolates the preview so it cannot touch anything outside itself.

Is my HTML uploaded anywhere?

No. Rendering happens entirely in your browser and nothing is transmitted or stored, which you can verify by turning off your Wi-Fi.

Can scripts run in the preview?

Yes, but only within the sandbox, which grants allow-scripts without same-origin access, so scripts are contained.

Limits

Renders self-contained HTML; external resources it references may be blocked by the page's security policy.

Related

The HTML-to-JSX tool converts markup; the HTML formatter tidies it.

Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.