Resources Hub » Blog » Email Deliverability: What It Is and Why It Matters

You’ve probably heard us talk about the importance of email deliverability, but do you know how it specifically applies to you, your email marketing strategy, and your customers?

Whether you’re constantly tracking your statistics or you’re just now hearing about this metric for the first time, remember that even the best email campaigns cannot be successful without following deliverability best practices. You could say that deliverability is the make-it-or-break-it of email, but don’t worry, we’re here to help you make it.

First, let’s jump in with the basics.

Email delivery vs. email deliverability

Email delivery and deliverability can be complicated and may, at times, seem part science and part magic. We can start demystifying these concepts first by defining them:

Email delivery is when an email is successfully delivered to the receiving server.

Email deliverability is when an email successful arrives in the person’s inbox.

It’s possible to have good email delivery but poor deliverability, because the email landed in a person’s spam folder rather than their inbox.


Email Service Providers (ESPs) will be provided some information why a message was rejected (bounced), based on the details the receiving server sends back in the error message.

We can then accurately measure delivery rates to know how many emails are accepted and how many bounce. Examples of bounced emails include a temporary delivery error (soft bounce) because the server is unavailable, or a permanent error (hard bounce) because the email address is no longer valid.


Delivery, however, is only the first part of the email’s journey to successfully arriving in the inbox. Campaign Monitor has an overall delivery rate of 99%. Although we are unable to know what percentage of emails arrive in the inbox vs the spam folder, we can make inferences by analyzing some key metrics for our emails.

Bounce rates (tracked by the ESP), open rates, unsubscribe rates, click-through rates, and spam complaints give the marketer insight as to how people react to and engage with their emails. Monitoring these metrics over time reveals trends in audience activity and engagement.

Engagement is the most important factor in email deliverability since it directly impacts sender reputation (both for the marketer and the ESP). A stellar sender reputation is key to great email deliverability.

Before we dive into how to work towards great email deliverability, it’s important to consider why email deliverability is critical to effective email marketing.

Why should we care about email deliverability?

Here are three important reasons why email deliverability matters to a marketer.

1. Successful deliverability equals successful email marketing.

Email deliverability is the foundation upon which email marketing is built. At a base level, a marketer is paying an ESP to send emails on their behalf but how a marketer manages their subscriber list and email program will determine whether or not the email is placed in subscribers’ inboxes.

As we previously mentioned in 70 email marketing stats every marketer should know, email generates the highest return on investment (ROI) for marketers, with a 4400% ROI and $44 for every $1 spent. Email clearly remains extremely relevant in today’s digital marketing landscape and has the potential to be a highly lucrative marketing avenue when employed strategically.

Marketers spend much time and effort crafting the perfect email and this effort is certainly worthwhile. Having the ideal ratio of text to images, considering the spacing, using an eye-catching font, personalizing the content for the target audience, and selecting the optimum sending time and frequency are all key factors in a successful email.

However, all that effort is wasted if the intended audience never opens the email because it never arrives in their inbox.

It benefits a marketer to manage their email program in such a way that inbox placement and open rates are optimized. Designing a thoughtful and attractive email only goes so far.

Marketers must ensure their emails are actually viewable to an interested audience. Achieving this end requires good deliverability and careful subscriber list management.

2. Win the inbox competition.

The email world is a very busy and, hence, a very competitive space. Individual senders compete with each other for emails to be both accepted by inbox providers like Gmail and then filtered to the inbox.

In March 2018, the Radicati Group estimated the number of email accounts worldwide at 3.8 billion, with about 124.5 billion business emails and 111.1 billion consumer emails sent and received each day. posted in February 2018 that 14.5 billion spam messages are sent globally each day.

More recently, Gmail posted in Product News that “1.5 billion people use Gmail every month, and 5 million paying businesses use Gmail in the workplace.” With so many individuals and businesses using Gmail—and so many spam emails being sent—safeguarding the inbox is paramount. Gmail’s machine learning algorithms block nearly 10 million spam and malicious emails every minute.

With an accelerating increase in email traffic and inbox providers implementing more rigorous filtering technology to secure their user’s inboxes, a marketer has to earn their place in the inbox. The savvy marketer knows they need to provide relevant and engaging content, delivered at the right frequency to an interested audience, and build long-term relationships with their subscribers.

See how Canopy provides personalized and relevant content to their subscribers, helping them find the perfect gift:

See how Canopy provides personalized and relevant content to their subscribers, helping them find the perfect gift

Image Source: Really Good Emails

3. Care about the audience experience.

Marketers are in competition with all other email senders and want to win their place in the inbox. For email marketing to be successful, people must actually open an email and engage with the content. Thus, if you want to be successful, a marketer must consider the experience from the recipient’s point of view.

Consider content

Considerate marketers only send emails people actually want and only send to fully opted in lists. Sending emails to non-permission based lists will result in low open rates, high unsubscribe rates, and high spam complaints, all of which indicate an unsuccessful email.

Such poor stats will have an ongoing negative effect on sender reputation and will impact the sender’s deliverability in the future. We’ve written more about collecting opted in email addresses in our permission to send post.

See how AutoTrader is upfront about updating subscriber permissions in this email:

See how AutoTrader is upfront about updating subscriber permissions in this email

Image Source: Really Good Emails

Consider frequency

A marketer also needs to balance maintaining their subscriber’s interest by sending regularly without sending too often, which can cause inbox fatigue. Giving subscribers greater control over both email content and email frequency by setting up a preference center is an excellent way to remove the guesswork.

The more information you collect from your audience, the more their experience can be customized. A customized experience increases engagement.

A great way to collect this information is to include a link to the preference center in the permission reminder text, along with the unsubscribe link. Recipients really appreciate this kind of consideration and it can also reduce potential spam complaints.

Consider preferences

Finally, a marketer’s relationship with a subscriber is a two-way street and a healthy mailing list is a dynamic entity. It’s important to nurture new subscribers and make them feel welcome, while also rewarding active subscribers and maintaining their interest. Subscribers may also decide to part ways with a sender as their needs and interests change.

It is important to regularly check in with the less active people on a list and give them the opportunity to re-engage or opt out of future emails. If left unchecked, the number of inactive people will grow.

Continuing to send emails to them will then negatively affect sender reputation and impact deliverability, even to active subscribers.

Wrap up

While the question “If a tree falls in a forest and no one is around to hear it, does it make a sound?” may be rhetorical, there is nothing ambiguous about the question “Will you have good ROI if your emails don’t land in the inbox and no one opens your email?”

Marketers always seek to maximize the efficiency of email marketing and the laws of supply and demand apply to email as well. Constantly monitoring the activity and engagement levels of subscribers allows a marketer to better understand what the subscriber wants and then tailor emails to cater to their needs.

The end result will greatly improve your deliverability.


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This blog provides general information and discussion about email marketing and related subjects. The content provided in this blog ("Content”), should not be construed as and is not intended to constitute financial, legal or tax advice. You should seek the advice of professionals prior to acting upon any information contained in the Content. All Content is provided strictly “as is” and we make no warranty or representation of any kind regarding the Content.
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