Newsletter HTML Previewer
Preview newsletter HTML before sending and catch layout issues in your email campaign.
Sandboxed iframe preview: no scripts, no access to the rest of the site, everything stays local.
Complete Guide & FAQ
What is the Newsletter HTML Previewer?
Paste the HTML your designer, agency, or email marketing platform sent you and see it rendered exactly as it will look before sending it to your contact list, with no test send required.
How it works
- Paste the full HTML code: including embedded styles, exactly as delivered to you.
- Isolated rendering: the preview runs in a separate iframe, so the newsletter's styles never clash with the site's own.
- One click: a Render button to refresh the preview every time you edit the code.
Frequently Asked Questions (FAQ)
Is it safe to paste HTML from a third-party vendor?
Yes. The preview renders inside a sandboxed iframe with no permission to run scripts or reach the rest of the site, so no embedded code (like a tracking pixel's JS) can affect you.
Can I paste a full HTML document, with <head> and <style>?
Yes. Unlike pasting raw HTML into a normal page, the iframe interprets the full document (doctype, head, and styles included) the same way the recipient's email client or browser would.
Is the HTML sent to any server?
No. All rendering happens in your browser; the content you paste never leaves your machine.