The Strong Link Between Email Engagement And Deliverability

Email engagement. 

This is the key to the success of your email campaigns. 

If you can lock in your audience’s engagement, you improve email deliverability and get your emails into more inboxes. That simple. 

Except, it’s not all that simple because humans’ attention has become like meth-addicted squirrels. Harder and harder to hold onto. Every time a subscriber chooses not to interact with your email campaign, or move it to the spam folder, or delete it without reading, your email deliverability takes a hit. 

No wonder you worry. Because email deliverability reflects how effectively your emails reach your recipients’ inboxes without getting marked as spam or blocked. 

So, what’s the deal with email engagement metrics impacting your email deliverability? Let’s dive deep. 

Email Engagement And Email Deliverability: What’s The Connection?

Email experts predict in this Email Mavlers’ infographic–Email marketing trends in 2025:

Other inbox providers—like Gmail and Yahoo—will roll out new, stricter deliverability standards to improve the email experience for customers. 

If bulk senders don’t comply with these standards, the providers will block their emails. No joke—Gmail and Yahoo block billions of unwanted emails daily. If not blocked outright, they may deliver it to customers’ spam folders. Any which ways, subscribers will not see your painstakingly designed email templates. 

Translation: maintaining strong email deliverability is mandatory if you want email to remain an effective marketing channel. 

There is a good reason for you to be anxious about the stricter deliverability rules if your emails are suffering from chronic, low subscriber engagement. Because there is a huge overlap between email engagement and deliverability. 

1. High Email Engagement Signals Sender Reputation

Email service providers (ESPs) are judging you as an email sender. The score they give you is called the sender reputation. Think of it as the credit score. 

But why does this score matter?

ESPs do not want their inbox users to receive massive spam emails. For the simple reason of making the user experience more secure and user-friendly. To do that, they run reputation checks to decide if the email sender is credible and where to place their emails. 

If your sender reputation score is high, ESPs feel your emails are inbox-worthy. You have their trust. They are more likely to deliver your emails to subscribers’ inboxes. 

The reverse is also true—and tragic.

If your brand has a low email sender reputation, ESPs are less likely to deliver your emails to someone’s inbox. Instead, your emails could end up in the spam folder, or worse, they might not reach your customers. 

Being labeled spammy is not a good feeling in itself. But it also hurts your email deliverability. Having a poor sender reputation means your email campaigns won’t end up in your subscribers’ inboxes.

That’s why brands and email marketers should never ever lose sight of their sender reputation and how it relates to the engagement metrics of emails. 

The more subscribers open, click, respond to, and forward your emails, the better the engagement. An engaged audience signals mailbox providers that your campaigns are valued and rightfully belong in the inbox. 

On the other hand, when your subscribers ignore, delete, or unsubscribe your messages, it drags down the engagement levels. Consistently low engagement rates cause ESPs to think of your emails to be less relevant or less valuable, marking them as spam. 

Said another way: getting your subscribers to engage with your email content will boost your sender reputation, which in turn will improve your email deliverability. 

2. High Email Engagement Improves Inbox Placement

When your emails leave your mail server and head to your subscribers’ inbox, inbox placement determines the last mile of this journey. Whether the email goes to the primary inbox, spam, promotions, or another folder.

Naturally, as an email sender, you want your emails to land in the primary folder. Because that’s where they get the maximum accessibility and visibility.

To earn the privilege of reaching primary inboxes, you’ve got to keep your subscribers engaged and spam complaints low. This is to show your emails are wanted. 

Focusing on these things increases the chances that mailbox providers will recognize you as a reputable sender worthy of inbox placement.

If you have low inbox placement, an ESP may be more likely to consider your email marketing to be spam—even if they aren’t. 

Ending up in junk feels like a slap in the face. Not only because it lowers your email deliverability, but also because subscribers miss important information, and it’s a big blow to the brand reputation. 

3. High Email Engagement Keeps Spam Complaint Rate Low

Recipients perceive intrusive or unwanted emails as spam. If they don’t wish to hear from you anymore and still choose to flag you as spam rather than unsubscribing, it’s either because you’ve pestered them enough or it’s hard to unsubscribe. 

Yahoo and Google sender requirements in 2024 stipulate a 0.3% threshold for spam complaint rate. Below 0.1% is best. Meaning, if three out of 1,000 emails you send receive spam complaints, you have reached the 0.3% threshold. 

The more often your emails get flagged as spam, the more likely mailbox providers are to believe that you are spamming. Your inbox placement takes the flak. And even more emails land in the junk folder. 

If the complaint rate reaches 0.3%, you’re in soup. That’s when you’re at risk of being blocklisted. This sends you into the downward spiral of poor email deliverability. 

Wrapping Up 

There are many possible reasons why a subscriber stops engaging with your emails. That’s a whole new can of worms to open another time.

For now, remember this: High email engagement is a loud signal to email service providers, positioning you as a trusted sender.

This boosts your deliverability into primary inboxes. When spam filters see that your email contacts are genuinely engaged, they recognize that your content is relevant and offers real value to subscribers.

The best part: increased engagement does not just lead to better deliverability, it forms stronger customer relationships and drives more sales, too.

Also, you can read: How to Build High-Converting Email Journeys in Salesforce Marketing Cloud.