Use the inbox and spam filter test

Learn how to test your campaigns with our inbox and spam filter test.


The inbox and spam filter test is a paid-for service provided by our partner, Email on Acid.

Inbox tests allow you to see how your campaign looks in different email clients, and the spam filter tests let you see whether your campaign is likely to pass or fail various spam filters.

Inbox and spam filter tests work only if you have a contact with the email address of your account holder. We use this email address to generate the results of the test.

The difference between preview and inbox and spam filter testing

The Inbox and spam filter test tool doesn’t support views for advanced personalisation and dynamic content; it should be used to see how campaigns look on different types of devices. Use the Preview button to view your advanced personalisation and dynamic content.

Order an inbox and spam filter test

To order an inbox and spam filter test:

  1. At the Test step of creating an email campaign. Find the header Inbox and spam filter test, and select Order test.
    You'll see the current cost of a test before you complete the order.
  2. Inbox and spam filter tests can take between 15 and 30 minutes to return results. Therefore, if you don't want to wait for the results, select to be notified by email or by text message when the tests are complete.
  3. To view the number of results that have been returned so far, go to Campaigns > Inbox test results.

View the results of an inbox test

  1. Go to Campaigns > Inbox test results
  2. Next to the campaign, select View. Or select the link in the notification email we send you.
  3. Hover over a preview image for an email client and select View to see how your campaign looks in that email client.

Where available, you have the option to see more than one preview for an email client. Use the options in the header to view the following:

  • The campaign with images turned on/off
  • The campaign in preview/full-screen mode
  • For webmail clients, such as Gmail or, you can choose to see the campaign in different browsers

Viewing the results of a spam filter test

  1. Go to Campaigns Inbox test results.
  2. Next to the campaign, select View. Or select the link in the notification email we send you.
  3. Select the Spam filters tab

The different spam filters are displayed in two sections: 'Business filters' and 'Consumer filters'.

The result for each filter can be 'passed', 'failed', or 'unknown'.

Campaigns can fail the spam test for a number of reasons. Unfortunately, there's no way to determine the exact reason why it's failed.

The spam filter test runs a simulation by sending a version of your campaign to various email clients. Campaigns with a 'failed' score indicate that the email wasn't received in the inbox, which means the email could have been blocked or sent to the junk folder for that particular email client. Spam filter results can often be pessimistic as the recipient email from the test hasn't interacted with the sender previously. Marketing to historically engaged contacts should help mitigate some failed tests. 

If a result is 'unknown', it means the results for that spam filter are unavailable.

Here's a list of all the spam filters that a campaign is tested against:

Business filters

  • Baracuda
  • Cloudmark
  • Google Apps
  • Iron Port
  • Symantec Cloud
  • Symantec Messaging Gateway (formerly Brightmail)

Consumer filters

  • AOL
  • Apple Mail 10
  • Apple Mail 11
  • DKIM
  • Fastmail
  • Gmail
  • GMX
  • Hustmail
  • Outlook 2003
  • Outlook 2007
  • Outlook 2010
  • Outlook 2013
  • Outlook 2016
  • Spam Assassin
  • SPF
Did you find this article helpful?

Can we help?

Thanks for using Dotdigital. If you need more help or support, then contact our support team.