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Email Checklist: Avoiding the Junk Folder

When a customer experiences bulking (the technical term for when emails are delivered to a junk/spam folder), there are some standard things that the team here at ClickDimensions checks first. If you are having problems with delivery to your recipients’ inboxes, see if one or more of the items on our checklist below applies to your emails. And even if you aren’t having difficulties with email deliverability, it’s worth a read through of this checklist to remember these things for your next campaign.

1. SPF Record

If you have a SPF record set up for the sending domain, it should include the ClickDimensions domain (customers.clickdimensions.com) and it should be free of errors. There are several free sites you can use to check your SPF record: Kitterman, MxToolbox, wiseTools. These sites will check for number of lookups, syntax, redundancies and empty lookups. If you would like more information about how to update your SPF, we have a help article for that.

If you don’t have a SPF record set up for your sending domain, it might not have as big of an impact as a broken SPF record, but we still recommend setting one up as a best practice. Some email providers will flag a sender if there is no SPF record set up.


An email CNAME is more optional than the SPF record. A CNAME will rebrand the redirect links in your email to coordinate with your sending domain. When the sending domain and the link domains match, it makes the email look professional and polished. Not having a CNAME set up will not affect deliverability for an email. However, a broken CNAME record can create 404 errors and result in your email being flagged as spam. CNAME records require set up in both the ClickDimensions application and the DNS records for your domain. Read our CNAME help article for more information.

3. Links

There are several things you need to keep in mind when including links and buttons in your email.

  • Make sure all the URLs resolve to a website (and hopefully the correct one). A URL that is broken or that leads to a page that is no longer available can result in a 404 error. In addition to it being a poor customer experience, a 404 error will cause a spam filter to flag your email. Test, test and test again before you send a campaign.
  • Don’t use short URLs. Short URLs are great for social media where characters or screen space is limited, but they are also a tactic used in phishing emails, which means spam filters will flag your email as spam.
  • Most sensitive spam filters (think financial institutions and government agencies) will also flag full URLs since all links in ClickDimensions use a redirect URL to track metrics. For example, if you have www.microsoft.com in the email copy, the redirect URL for this may actually be elink.clickdimensions.com. The discrepancy with URLs can cause some emails to be flagged. We recommend instead to hyperlink a word or phrase for text links: Microsoft.

4. Text Version

One of the easiest things you can do to reduce your spam score (more on that later) is to include a text version of your email. Mailbox providers and spam filters like to see emails that come with a HTML and text version (called Multipart MIME). If you are unfamiliar with how to create a text version of your HTML email, you can read our help article about text versions.

5. HTML    

Spam filters parse the HTML of an email to determine if there are any elements that look like phishing. If there are errors in the HTML, the filter will be unable to parse it and will most likely flag the email as a result. This isn’t an issue I run across very often because everyone is testing their emails before they send them (right?), but it’s worth noting.

6. Images

There are just a few things to keep in mind about images in emails:

  • Always have descriptive Alt Text for images. Spam filters will check for this, but almost more importantly, a recipient can still understand the message and navigate the email with images turned off.
  • Balance images with text. I’ve seen some really beautiful image-heavy emails, but an email still needs some text to get your message across to those recipients that have images turned off. Also, your spam score may increase slightly if the email is mostly images. Include a few sentences and maybe a text link to ensure all audiences can read your email.

Here is how one of our ClickDimensions Newsletters looks with images turned off:

Newsletter without images

You don’t get to see the pretty pictures for each topic, but with background images, Alt Text and text, you can still understand and navigate the email.

7. Spam Score

The SpamAssassin spam score is a widely used measurement to predict how your email may be received by various mailbox providers and ISPs. You can view the spam score and which rules were triggered by using the test email function in ClickDimensions. A spam score ranges from zero to 10. We like to see spam scores of three or less.


Mail-tester is a free, user-friendly tool that you can also use to see your SpamAssassin spam score for an email. Mail-tester will give you a custom email address where you send your email and then you can view the report on their website. Tip: the email address can be reused. Create a contact with the Mail-tester email address and include it on the marketing list you use for testing.

About the Author:

Julie Turner is a Senior Email Deliverability Engineer at ClickDimensions.


  1. Huguette January 18, 2018 at 4:24 am - Reply

    Hi Julie,
    You’re suggesting to use Mail-Tester but could you precise what does it makes that your Spam Assassin Report tool is not doing already ?
    thank you, have a nice day,

    • mm
      ClickDimensions Marketing January 25, 2018 at 8:12 am - Reply

      Great question, Huguette! Both tools (our internal spam report and Mail-tester) are based on Spam Assassin but our internal tool is testing the content for the email template only. It will check mostly the HTML related rules about fonts, images, colors, text to image ratios, some of the link rules, and if the template has both HTML and text parts. Mail-tester takes into account all the items that our tool tests PLUS it will check items related to the domain (SPF, DKIM, rDNS, DMARC). Mail-tester will give a more complete picture because it’s able to test the full final email header. It also provides some of the information in a different format which may be easier to interpret in some cases (Spam Assassin has never had very human-friendly error messages).

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