Email HTML Previewer
Paste email HTML and preview it on desktop and mobile widths, with checks for size, alt text, fixed widths and stripped tags.
Paste email HTML above to see it rendered and checked.
- HTML size
- 0 B
- Images
- 0
- Missing alt
- 0
- Links
- 0
Deliverability & rendering checks
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Preview
Plain-text version
How it works
Paste the HTML of a marketing email, a transactional template or an export from your ESP and it is parsed and drawn instantly in a sandboxed frame, so you can see the real layout without sending a test campaign to yourself. Switch the preview width between a 600 px desktop column and a 375 px or 320 px phone to check that your tables, buttons and font sizes still work on a small screen. Remote images are blocked by default, exactly the way Outlook and many Gmail accounts show a message the first time, so you can confirm the email still makes sense before anyone clicks "display images".
Alongside the preview you get the checks that matter for the inbox: total HTML size against
Gmail's 102 KB clipping limit, images with no alt text, hard-coded widths over 640 px, whether
you rely on a <style> block or media queries that some clients strip, and
tags such as <script> or external stylesheets that every mail client
removes. The plain-text version is generated from the same HTML with links expanded, ready to
paste into the text part of your multipart email.
Everything runs in your browser with the built-in DOMParser and a sandboxed
iframe — the HTML is never uploaded, the frame cannot run scripts, and with image blocking on
no request leaves your machine. That makes it safe for customer-facing templates that still
contain real names, order numbers or unsubscribe tokens.
Frequently asked questions
How do I preview an email template without sending a test email?
Paste the HTML into the box above and it is parsed and rendered instantly in a sandboxed frame in your browser. Switch the preview width between a 600 px desktop column, a 375 px phone and a 320 px narrow phone to check that your tables, buttons and font sizes still hold up. Because nothing is uploaded and no message is sent, you can safely check templates that still contain real names, order numbers or unsubscribe tokens, and you can iterate as often as you like without burning seed-list sends.
Why does Gmail clip my email and how big can the HTML be?
Gmail truncates a message once the HTML passes roughly 102 KB and replaces the rest with a 'View entire message' link, which usually hides your unsubscribe link and any tracking pixel at the bottom. The size check above measures the exact byte size of what you pasted and warns you once you get within 80% of that limit. The usual fixes are removing editor comments and unused CSS, shortening base64 images, and trimming repeated inline styles.
Why are the images not showing in the preview?
Remote images are blocked by default because that is what Outlook and many Gmail accounts do the first time someone opens your email — you see a grey placeholder instead. It is the honest test: if the email makes no sense with images off, add real alt text and keep the key message in live text. Untick 'Block remote images' to load them, or leave it on to keep the page fully offline, since with blocking enabled no request leaves your device.