New
HTML Viewer
Paste HTML and watch it render live in a sandbox, at laptop, tablet or phone width.
How it works
Email HTML Previewer
Paste your email's HTML to see it on desktop and mobile, in light mode, in its own dark mode and with the color inversion some apps apply. Then fix what the checks find before you hit send.
Paste HTML or load the sample to see the preview.
Checks
Inbox preview text
Plain-text version
for the text/plain part
- 01
Paste your email's HTML, upload an .html file, or load the sample.
- 02
Switch between Desktop and Mobile, and between Light, Dark and Auto-invert.
- 03
Turn images off to see what people with blocked images get.
- 04
Work through the checks, then copy the plain-text version for your sending platform.
About this tool
Why email HTML needs its own checks
Email clients are far less capable than browsers. Outlook for Windows renders with Microsoft Word's engine, Gmail removes external stylesheets and many CSS properties, and most clients strip scripts, forms and iframes. Gmail also clips any message over about 102 KB, hiding everything after the cut, often including the unsubscribe link. That's why reliable emails still use tables for layout, inline styles and absolute image URLs.
This previewer renders your HTML in a sandboxed frame at desktop and phone widths, and simulates the two kinds of dark mode: clients that apply your prefers-color-scheme styles, and apps that invert light colors on their own. Alongside, it checks for problems that break in real inboxes, shows the preview text people see after the subject line, and builds a plain-text version for the text/plain part. It's a fast first pass; for a release, still send tests to the clients your audience uses.
Desktop and mobile
See the email at full width and in a 375 px phone frame, with your responsive styles applied.
Two kinds of dark mode
Your own dark styles, and an approximation of Gmail-app and Outlook.com color inversion.
Inbox-ready checks
Gmail clipping, stripped tags and CSS, Outlook image widths, alt text, links, viewport and accessibility.
Preview and plain text
See the inbox preview text, toggle images off, and copy a generated plain-text version.
FAQ
Frequently asked questions
Is this the same as testing in real email clients?
No. It renders in your browser and simulates widths and dark mode, which catches most layout and content problems quickly. Clients like Outlook for Windows render differently from any browser, so send real tests before an important campaign.
Why does Gmail clip my email?
Gmail clips messages whose HTML is larger than about 102 KB. Bloated markup from builders, long inline styles and tracking code all add up. The size check shows how close you are.
How do I support dark mode in email?
Add <meta name="color-scheme" content="light dark"> and a @media (prefers-color-scheme: dark) block with !important overrides. Apple Mail and Outlook for Mac use them; Gmail's apps ignore them and invert colors themselves, which the Auto-invert preview approximates.
Do remote images load in the preview?
Yes, from your browser, as they would in an inbox. Untick Images to block them and see your alt text instead.
Is my email uploaded?
No. The preview and checks run in your browser and the HTML never leaves your device. Scripts in the HTML don't run.
Missing something?
Tell us the tool you wish existed.
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