Using the inbox and spam filter test


The inbox and spam filter test is a charged service, which is provided by our partner, Email on Acid.

Inbox tests allow you to see how your campaign will look in different email clients, and spam filter tests allow you to see whether your campaign would 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.

Ordering a test

  1. From the 'Test' step of creating an email campaign, click Order test. The current cost of a test is displayed 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 the option 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.

Viewing the results of an inbox test

  1. Go to Campaigns > Inbox test results
  2. Click View next to the name of your campaign. Or, click the link in the notification email that is sent to you (if you selected that option).
  3. Mouse over a preview image for an email client and click View to see how your campaign will look in that email client.


Where available, you'll 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 and click View next to the name of a campaign.
    Or, click the link in the notification email that is sent to you (if you selected that option).
  2. Click 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
  • Yahoo
Have more questions? Submit a request


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    My campaign failed postini with a score of 0.00236. Can anyone tell me why?

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    Hi Graham,

    Postini’s a bit of a gnarly spam filter and most email marketing software will regularly fail it; there is some good news though:

    • We report a near worst case scenario for Postini; if you do have any subscribers with Postini filtering then they have the control to adjust their own Postini set up. If they’ve added you to their whitelist, have adjusted the settings to a more typical set up, or have previously opened your mail then your email will, in all probability, hit the inbox
    • Postini is being retired this year  (all users will be transitioned to Google Apps) — we’re keeping an eye on this and will look to have an update when we (and our testing partners, Litmus) have more news as to how this affects users of Google Apps

    We’re looking at the way we display Postini reports; as the ‘worst case scenario’ approach does appear to cause some concern.

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    Just had the results back from my next campaign, it's failed AOL mail, any insight as to why?


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    i tried sending mails but it appears as a junk/spam mail. how can i ratify that and send mails straight into inbox.

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    Hi, I've just run the litmus test and all the results look okay apart from Outlook2013 which is blank if you have images turned on. With images off the text is displayed correctly. Any idea why this would be? The spam filter for Outlook is returning a score of 5 which should pass.

    Thanks for your time.


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    I've got the same problem as Lisa Logan above. Any clues?

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    Sorry to hear you’ve both experienced the same issue with this. I’ve run an inbox and spam filter test and all was well with Outlook 2013 with images on (tested in Chrome v45.0.2454.99 m on Windows 8). It may have been a temporary glitch but if you’re still experiencing problems with it then I recommend contacting with the details and they’ll be happy to look further into it for you.

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    i have run a few spam tests (Litmus thru the platform and Email on Acid) for various client accounts, some of which are on dedicated IPs with great sending reputation and some on regular pools... it seems many of them fail Google Apps, Office365, GoDaddy, Google Inbox. Is this normal?