Your email can look correct in preview but different in Gmail, Outlook, Apple Mail, or another inbox. In most cases, Bloomreach sends the expected email content, but the receiving email client applies its own rendering rules after delivery.
This article explains why that happens, what each preview mode actually shows, and how to troubleshoot the difference.
What each preview option shows
When you are testing an email in the Design or Test section of the email editor, you have multiple testing options that have different goals.
Editor
The view of the email in the Editor tab of the Design section may differ from the test versions below; this difference does not indicate an issue with the template itself. You should not rely on how the message appears in the Editor itself, but rely more on the test previews.
Overview
The Overview tab in the Test section shows a rendered preview for a specific customer, including personalization. If the email uses an on-event trigger, the platform can use a matching past event to render that preview.
Email Previews
The Email Previews tab in the Test section shows screenshots of your email in specific environments, such as Gmail on iOS or Outlook. These previews help you catch visual issues, but they must be regenerated after template changes.
Send test email
A test email shows how the message appears in a real inbox. We recommend sending a test email before launch, because inbox rendering can differ from previews.
Why does the inbox version look different?
The email client changes the rendering
Gmail, Outlook, Apple Mail, and other clients can change spacing, colors, fonts, backgrounds, and images when they render the same HTML. This is especially common in dark mode.
Your previews are outdated
If you changed the template after generating previews, the Email Previews tab may still show an older version until you regenerate it.
Preview modes do not use the same data context
If your email depends on trigger-event data, only the Overview tab can use matching past event data for rendering. This behavior does not apply the same way in Send test email, preview link, or Email Previews.
Dark mode overrides your design
Dark mode behavior is controlled by the recipient’s email client, not by our platform. Because of that, the same email can look different across Gmail, Outlook, and Apple Mail, even when the preview looks correct.
How to troubleshoot the difference
1. Confirm which preview you used
Check whether you are comparing the inbox version against Overview, Email Previews, or a test email. These modes are not identical and should not be used interchangeably.
2. Regenerate Email Previews
Go to Test > Email Previews and regenerate the screenshots after your latest changes.
3. Send a real test email
Send a test email to the affected inbox provider and device. This is the best way to confirm how the email is rendered in the real email client.
4. Check whether trigger-event data is involved
If the email uses on-event data, review it in Overview alongside a customer with a matching event. If no matching event exists, the rendered result can differ from what you expect in the live scenario.
5. Compare light mode and dark mode
If the issue appears only in dark mode, compare the email across clients and test whether background images, white content areas, or other design elements are being overridden.
6. Inspect the original email if needed
If screenshots are not enough, extract the original email. The original email shows the exact HTML, headers, encoding, and delivery metadata received by the mailbox provider, which helps confirm whether the issue started in the template or during inbox rendering.
What to share with support
If you still need help, include:
- A link to the email campaign or template.
- The affected inbox provider, app, and device, for example, Gmail on Android or Outlook on the web.
- Whether the mismatch appears in Overview, Email Previews, Send test email, or only in the live inbox.
- Screenshots of both versions.
- The original email source, if the issue is still unclear. Use How to extract the original version of the email guide.
Summary
Rendering differences between preview and inbox are usually caused by the receiving email client, outdated previews, or differences in available event data. Regenerating previews, testing in the affected inbox, and checking dark mode behavior usually show whether the issue comes from the template itself or from how Gmail, Outlook, or another client displays the email after delivery.