New spam filters and email validation features


We’re pleased to announce a number of small, but significant, changes to improve spam filtering and email previews in Litmus!

Outlook spam filtering has been added. Outlook (along with a few other desktop spam filters) utilizes a self-learning filter to determine what you think is spam. While this is great for individual users, it’s not consistent nor reliable for use across thousands of tests on our servers. Instead, we’ve added in hundreds of spam rules that have been published by Outlook. Whenever the content in your campaign triggers one of these rules, we’ll provide you with feedback on what can be changed to make your email look less “spammy” to Outlook.

In addition to these Outlook rules, we’ve also added in hundreds of extra Spam Assassin rules and explanations. Many of these involve blacklist lookups, less common words and different languages. Again, you’ll find these explanations along with some feedback to help troubleshoot your campaigns in the right-hand column of your spam analysis test result.


In addition to these more traditional spam filter enhancements, we’ve also added in link and image checking, as well as HTML validation for email previews. For both link and image checking, we’ll locate links to both URLs and externally hosted images and follow them to check they resolve properly. For now, these checks appear as an additional spam filter in the spam analysis section of your test. Any broken images, links or validation issues will appear as warnings in the right-hand column. Keep in mind that if you’ve used non-standard HTML or deprecated tags to ensure cross-client compliance and graceful degradation in Outlook 2007, these may appear as validation errors in the W3C checks.


All of these improvements are effective immediately and are accessible in your Litmus account. In order to run these additional checks and spam filters, simply check the “comprehensive spam filter check” box when starting a new email test.

We hope that these changes improve the feedback Litmus is providing when your emails fail certain spam checks, and make it easier to troubleshoot your campaigns. As always, we welcome your questions, comments and feedback.