How to use the html email preview
Inspect your email before a test send. This free HTML email preview keeps your source beside a simulated message so you can check the hierarchy, spacing, links, and reading experience without signing in.
- Paste a complete HTML document or an email fragment into the editor. Changes appear immediately in the preview.
- Enter the sender name, subject, and preheader. Read them together in the simulated inbox before opening the message.
- Switch between desktop and mobile widths. Look for oversized images, wide tables, cramped buttons, and text that becomes difficult to scan.
- Switch appearance to inspect a dark mode approximation. Enable remote images only when you trust the image URLs.
- Send the final email to real test inboxes. Compare the received message with this browser preview before launching your campaign.
What a browser preview can tell you
A browser preview is useful for checking content hierarchy, obvious overflow, responsive CSS, and the relationship between your inbox copy and the message body. Keep your most important information near the beginning and give each section a clear purpose. Check images with loading disabled, because many recipients block images or read on a slow connection. Meaningful alt text and selectable body text should carry the message even when artwork is unavailable.
Why real inbox testing still matters
Email clients do not share one rendering engine. Some Outlook versions use Word based rendering, while Gmail and Apple Mail handle CSS differently. This tool uses your browser and cannot reproduce every client restriction, account setting, or forwarding behavior. A successful browser preview does not certify compatibility. Send tests through the same platform and sending domain you plan to use in production, then inspect the received HTML on the devices your audience actually uses.
Previewing dark mode
The appearance toggle intentionally approximates a dark reading surface. It is not a simulation of any specific client color inversion algorithm. Check logos with transparent backgrounds, dark text embedded inside images, button contrast, and borders that disappear against a dark surface. Preserve readable fallback colors and test light and dark logo variants in real inboxes. Avoid assuming that a dark mode media query will be honored by every recipient.
Privacy and safe previewing
Your pasted content is processed locally and is not submitted to a rendering service. The preview runs in a sandbox with scripts, forms, and navigation disabled. Remote images are blocked by default because requesting an image can disclose your IP address or trigger a tracking pixel. If you enable them, the browser contacts the image host. The surrounding Ternloop website may use ordinary site analytics; it does not intentionally send the contents of these editor fields.
Common questions
Does this reproduce Gmail or Outlook exactly?
No. It is a browser approximation. Use actual Gmail, Outlook, and Apple Mail accounts for final rendering tests.
Why are my images missing?
Remote images are blocked initially. Enable them only for trusted URLs. Relative image paths also need to be replaced with publicly accessible HTTPS URLs.
Is pasted HTML executed?
Scripts and active embeds are removed from the preview, and the frame is sandboxed. Your original source is not rewritten or certified safe to send.