What Is Email Deliverability & Why Is It Important? | Episode 1

What Is Email Deliverability & Why Is It Important? | Episode 1

If you’ve been in the email marketing game for any time, you’ve probably heard about the importance of deliverability. But do you know exactly how it applies to your own email program and affects your relationship with inbox providers, your sending platform, and your subscribers? In this first iteration of a new series on deliverability, we’ll break down the basics of this topic to give you a strong foundation of knowledge to become an email hero in your organization.

Email marketing is about more than creating and sending messages. The goal of any successful email program is to reach the right audience with messages they want at the right time. This includes making sure that your subscribers actually receive the message instead of being filtered to the spam folder.

What is email deliverability, exactly?

We wish we could say that email deliverability is as simple as obtaining a single-number score from a third-party service, but sadly it’s not. Cue the violins. To better understand how to hit the inbox more consistently, it’s important to define deliverability. We’ll break down what it is and what it isn’t by looking at three categories: delivery, deliverability, and placement

Delivery rate

Delivery rates, also called the Acceptance Rate, confirm that your mail has been accepted into the Mailbox Provider (MBP)’s servers. MBPs are also known as Internet Service Providers (ISPs) — like Gmail, Hotmail and Yahoo.

MBPs actually send a message back to you that confirms that the email has either been accepted into their servers or rejected.


The “deliverability” piece — what people refer to as ‘measuring inbox placement’ — is what happens after that point. Unlike the delivery rate, MBPs do not send any feedback that lets you know if your message landed in the inbox or the spam folder.


Placement refers to which “tab” a message goes to within a subscriber’s inbox in Gmail and Outlook.


When enabled, Gmail tabs organize your inbox by sorting emails into preset categories such as Primary, Social, Promotions, as well as Updates and Forums.

What Is Email Deliverability & Why Is It Important? | Episode 1


Outlook also offers a tabbed view in the inbox, with categories including “Focused Inbox”, “Promotions”, “Social” and “Newsletter.”

What Is Email Deliverability & Why Is It Important? | Episode 1

Much like the deliverability rate, MBPs do not give feedback to let you know where your email landed within their Inbox tabs. To gauge this, marketers typically rely on a multitude of data points, including their engagement metrics, blacklist checks, postmaster tools, as well as various forms of Inbox Placement testing.

Our Kickbox Deliverability Suite was developed with this kind of holistic approach to monitoring in mind.

Get your free consultation today to see if the Deliverabilty Suite is right for you.

Why is email deliverability important?

Why should we care?

Though deliverability isn’t always at the forefront of our minds, there are a few key reasons that deliverability is an email marketer’s best friend. The main reason is because email has the highest ROI compared to any other digital marketing channel. According to Litmus, every $1 marketers spend on email marketing, they receive $42 in return.

The ability to reach the inbox is the foundation for email ROI

Increased inbox competition, changing standards from mailbox providers, and changing markets are eating into the margins of brands that invest time, energy, and dollars into email marketing. That means marketers want higher opens, clicks, and conversions, but that can’t happen unless the mail actually lands in the recipient’s inbox. If recipients aren’t seeing your messages in their inbox, then they will not have the ability to engage with those emails, or your brand.

Good deliverability avoids wasted investment in email marketing

There are few things more frustrating than spending time and effort strategizing, creating, designing, and sending messages only to see that messages are going to the spam folder of recipients, or that you cannot deliver emails because you’re blocked by a certain MBP, or worse: you’ve been listed by Spamhaus.

Aside from the direct revenue lost from people not being able to engage with your emails, it’s important to also consider the less direct costs related with deliverability issues:

  1. Time spent mitigating the issue with the MBPs when your mail is being sent to the spam folder or getting blocked (and maybe also your ESP, if your account has been rate limited or suspended for violating their AUP).
  2. Customer complaints about missing emails means your support team will be busier, potentially requiring overtime to handle the ticket load.
  3. Possibly hiring a consultant to dig you out of that hole. Deliverability people can be expensive!

Good deliverability creates a virtuous cycle of improved metrics and higher ROI

MBPs are focusing on recipient engagement much more than they used to…both positive forms of engagement like opens, clicks and replies, but also negative ones like user complaints, deleting emails without opening, and even a lack of engagement. The days of using scraped or purchased lists or continuing to send to people just because they haven’t taken the time to unsubscribe are over.

By focusing on creating emails that your readers want to engage with and building an audience who finds value in your content, MBPs will very clearly be able to see that your emails belong in the inbox.

Once you’re consistently hitting the inbox thanks to following industry best practices and monitoring your stats to ensure you continue targeting the right audience, you’ll be able to build a larger and more qualified email list, which will inevitably lead to more revenue for your company.

MBPs need to distinguish malicious senders from non-malicious senders

The size of the internet and the sheer number of malicious emails sent each day is mind-boggling. Let me give you an example based on some facts previously shared by Google:

  • 50% of what Gmail receives each day is spam
  • They also receive more than 100M phishing emails per day, and 68% of phish received at Gmail has never been seen before
  • They block 10M emails per minute

So with all of this really awful email being thrown at MBPs each and every day, it’s important for legitimate senders to differentiate themselves from spammers and fraudsters by following industry best practices that help them collect a list of recipients who are highly engaged and taking actions that prove to the MBPs that they are loving your emails.

What affects email deliverability?

There are literally hundreds of factors that go into determining if your message will be delivered to the inboxes of your recipients or not. It’s not as simple as one little number like a sender score to rule everything.

Each MBP uses different algorithms to make their filtering decisions, but at a high level, they are working to ensure that each message they deliver is safe for their recipients, as well as wanted.

However, there are still a few key factors that affect deliverability that can help you build a solid foundation for inbox placement:

Reputation (IP and domain)

You’ll want to ensure both your sending IP and sending domain maintain a solid reputation. There are many ways to track this, from free tools that check your domain or IP against common blocklists, to reporting available directly from the MBPs such as Google Postmaster and Microsoft’s SNDS.

Sending Infrastructure

You’ll also want to ensure any ESP or internal mailing system you’re sending through is properly configured to create and send your emails as well as effectively manage all engagement data, including positive activity such as opens and clicks, as well as events that may impact your sender reputation such as bounces, unsubscribes and complaints.


Setting up an SPF and DKIM record on your sending domain is considered standard practice by MBPs. Think of these as your passport, driver’s license or other form of ID that tells Mailbox providers exactly who you are. It allows them to have a bit more confidence that the mail you’re sending is legitimate.

But keep in mind that spammers authenticate, too, so having a properly configured SPF and DKIM record will not give you a free pass to the inbox.

DMARC is a bit newer of an authentication protocol, but one that can help protect your sender reputation from spoofing and other forms of abuse while using your sending domain.

There are countless resources online for setting up SPF, DKIM and DMARC so check those out, or contact your ESP for assistance that will be specific to their platform.

List collection and management practices

Permission is so important for consistent inbox placement. Sending to recipients who haven’t signed up for your mail can have a huge impact on your engagement rates, and so can targeting people who signed up, but have stopped engaging with your emails.

If you are seeing low delivery rates (or, you could say, a high bounce rate) it could be a sign of poor data collection. Iif you’re seeing hard bounces, also called invalid addresses, take a close look at your list collection practices.

Low delivery rates can also be a sign of a sender reputation issue. If you’re seeing a soft bounce that mentions spam or refers to being blocked due to policy reasons, content reasons, etc.

If your delivery rates are solid, but you’re seeing open rates on marketing campaigns that are less than 15-20%, it’s time to take a look at your targeting.

We’ll dig deeper into ways you can reduce your hard and soft bounce rates, as well as optimize recipient engagement, in later episodes.

Content of your emails

Last but not least, is the content of your emails. Content includes the subject line and body, as well as the sender address and friendly From name and all of the links within your email.

While it’s important to note that most deliverability issues are not caused directly by the content within your emails, content does play a part.

Issues such as…

  • Links within the body of your email that have a poor reputation, or
  • HTML emails that only contain images but no plain-text

…can help drive your mail towards the spam folder.

But the age-old myth that messages will go to the spam folder simply because you used the word “FREE” in the subject line is false. While the use of this word might elicit a negative response such as a spam complaint from recipients if what you’re sending is not actually Free, the word itself is not the trigger. It’s the recipient’s response

Stay tuned for the next blog

If you’re going to be successful in the long-term with your email marketing, you’ll need to master email deliverability and how you can influence it – starting with understanding your sending reputation. Stay tuned for the next part of the series where we’ll explore more about sender reputation and how to improve it.

Get My Deliverability Consultation Today

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