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Avoid the Junk Folder with Spam Testing

Sometimes spam seems like the great unknown. There’s so much out there about spam—but it’s hard to narrow down what exactly is keeping your email from the inbox?

That’s what we plan to break down for you today.

What you’ll learn in this article:

What’s the difference between delivery and deliverability?

These two words often get used interchangeably—but they don’t mean the same thing.

Delivery tells you whether or not your emails were received by the servers of your subscribers’ inbox providers. An email counts as delivered if it did not bounce, regardless if it landed in the inbox or the junk folder. So your delivery rate is the percentage of the number of emails delivered divided by the number of emails sent.

Deliverability refers to whether your message lands in the inbox if your subscriber does receive your email. It’s based on your IP and domain’s setup, authentication, and reputation—so if something goes wrong, the burden is on your shoulders. (Walk through our deliverability best practices here.)

What do spam filters look for?

Spam filters remind me a lot of SEO (search engine optimization): Things are constantly changing, and we don’t have a lot of visibility into what exactly they’re looking for. Or maybe a better analogy here would be McDonald’s secret sauce recipe…

Anyway, here’s what we do know about what spam filters look for:


Sender reputation refers to the reputation of your email sending IP address and domain that signal to email inbox providers whether or not you’re a spammer. It’s based on factors such as the content quality, quality of contacts, and engagement levels of previous emails sent from your IP address and domain.


Email authentication looks at the source of an email to see if it’s valid. Also called domain authentication or validation, email authentication helps prevent spoofing and phishing scams (think: emails that look like they come from Amazon but don’t). This includes filters like SPF, DKIM, and DMART—all of which we check as part of Litmus Spam Testing.

Spam trigger words

These are words commonly found in spam emails. Think: things that have to do with making money from home (through scams—not remote work opportunities!), targeting people for financial opportunities like refinancing or debt elimination, or even hocking products with unrealistic expectations, like “works miracles” or everyone’s favorite emails for Viagra. While this is not nearly as significant as it used to be, it’s something to be mindful of.

Spam reports

Of course, spam filters are also looking at spam complaints. If people don’t expect to receive your email, you buy a cold list, you send too many emails, or people can’t easily unsubscribe, you may be marked as spam. Depending on how many people mark your emails as spam—and how often that happens—your emails could start to land in the junk folder.

You’ll also want to be mindful of spam traps. You might come across these emails if you purchase lists or scrape websites (which hopefully you don’t do!). But these can also show up through recycled emails. Think: your first email address that you never use anymore but still exists and may still be receiving emails from companies. These can be turned into recycled spam traps. This is another great reason to clean your list and set up re-engagement campaigns.

How Litmus Spam Testing helps you

We’re here to help! Litmus Spam Testing scans your emails against more than 25 different tests, identifies issues that might keep you from the inbox, and provides actionable advice for how to fix them. (Learn more about the spam filters we test against.)

Running a spam test is simple: Click “Start a new spam test” on the spam testing homepage, copy the list of seed addresses, and send your email from your ESP to those seed addresses. The results will populate in Litmus in less than 10 minutes.

Have ESP sync set up? You can choose an email from your drafts to send into Litmus when you start a new spam test.

5 tips for improving deliverability

1. Run re-engagement and inactivity campaigns.

As marketers, we want to be engaging people who are interested in our products or services—and ISPs will ding you if they see people are repeatedly getting your emails but not engaging with them. Beyond that, inactive subscribers can become an issue if the emails turn into spam traps. Segmenting inactive subscribers and running re-engagement campaigns can make a world of difference to your deliverability.

2. Clean your list.

Consider this the business case for list cleaning! Landing in the junk folder renders your entire email program ineffective—and with email marketing generating 36:1 ROI, you can’t afford to land in spam. (Using Litmus Email Analytics? In addition to cleaning inactive subscribers, you can also segment out subscribers with lower engagement and read time.)

3. Provide easy unsubscribe options.

This is probably a no-brainer for most of us, but I also got this in an email this morning, so covering our bases here.

4. Run spam tests.

This is not just a promotion for Litmus Spam Testing. This is a reminder that in the same way you’d check your credit card statement or get the oil change on your car, you should be making sure your email is set up to get delivered.

5. Ensure you’re complying with email regulations.

Depending on where you live and where you send emails, email laws and regulations may vary. Subscribing to the Litmus blog is a great way to stay up to date on changes to the email industry. 😉

Ready to avoid spam?

There you have it: practical ways to avoid spam. We hope you found these tips and tricks useful!

If you’re currently a Litmus Plus or Enterprise customer, go ahead: Run a spam test.

If you’re a Litmus Basic customer and would like to try out spam testing, reach out to our Support team. We’re happy to set up a free 7-day trial for you to experience Litmus Spam Testing firsthand.

If you’re not currently a Litmus customer and would like to try spam testing for yourself, try Litmus Plus for free for 7 days.