Email marketing is much more than just writing and sending great, relevant emails. For a technology that is so old, it’s a highly technical channel and paying close attention to details matters more than you’d actually believe.

Among these technical details, the most critical technical details you’ve gotta nail is email deliverability.

Whether you’re an email marketing agency or just use email marketing service as part of your lead generation and marketing strategy,  email deliverability is one of the most important aspects of your over all email marketing strategy you’ve gotta nail and one that’s overlooked quite frequently.

Why? Because there’s a lot more to email marketing services than you probably expect, and if you don’t get it right, your emails may never reach your subscriber’s inbox.

As the provider of best email marketing services, today we’re taking a deep dive into the nerdy, darkest world of email deliverability, and learn, establish how you can ensure that your subscribers get your emails whenever you press the “Send” button.

What is Email Deliverability?

The likelihood of your emails arriving in your subscribers’ inboxes is called email deliverability.

Your emails may easily land in your recipient’s spam folder without either of you realizing it. Based on ReturnPath’s 2018 Email Deliverability Benchmark Report, 15% of emails never make it to the inbox. Also, based on Cisco Talos Intelligence Group, 85.27% of all emails sent are considered as spam.

Image Courtesy: Cisco

You first need to understand how the process of sending an email works in order to fully understand why your emails may not get delivered. Here’s what your email service provider (ESP) does when you hit the “Send” button;

  1. ESP accepts your content in its mail server (commonly known as MTA).
  2. They send it to the recipient’s mail server through several cloud servers.
  3. It gets processed through spam filters before it gets to your recipient’s mail server.
  4. If all goes well, the email gets delivered to your recipient’s MTA.
  5. The recipient now can see the email in their inbox.

Coming to the question! Hate to burst your bubble, but the answer is “Not really.” 85% email deliverability simply means that 15% of your emails triggered spam filter(s) on its way and actually didn’t make it to the inbox of your recipients.

What’s actually happening is that 15 out of every 100 recipients are not seeing your emails unless they check their junk folder. That’s 15 fewer potential deals, 15 customers you won’t connect with.

Whose spam filter did my email trip?

Most of the ISPs have a very complex set of filters to identify spam and route it to the spam folder. But, other filters belong to the recipients who set up their own filter based on the sender name, words in the subject line or the domain the messages are coming from.

In both scenarios, your email went to your recipient’s spam folder. And only a small percentage of recipients regularly check their spam folder.

Delivery versus deliverability:

Is email delivery and email deliverability the same thing?

No, they are not the same thing.

While email delivery measures how many of your emails got delivered somewhere at an ISP, email deliverability measures the number of your emails that made it all the way to the inbox instead of the spam folder.

Currently, at 85% globally, the overall inbox placement is getting much better, based on recent deliverability reports. That’s much better compared to where we were before 10 years ago when email deliverability was below 80%.

How to Assess Your Email Deliverability:

You can use any of the following tools to test your organization’s email deliverability;

  • Sender Score: This tool works like a credit score for your email’s reputation. This tool, from Return Path, gives you a score from 0 to 100. The higher the number, the better your reputation and the higher your email deliverability rates, and vice versa.
  • MxToolBox: This tool analyzes the reputation of your outbound IP address, your email headers, and your SPF records. From all this, they create a comprehensive deliverability report flagging any problems you might have.
  • Mail Tester: This is quite a simple tool that analyzes your mail server, your emails, and your sending IP. Based on this analysis, it provides you with a detailed report of what’s configured properly and what’s not.

With the information given by these tools, you’ll have a good understanding of your email deliverability, when you have any issues, what they are.

How to Improve Your Email Deliverability:

Good Infrastructure:

Infrastructure is the foundation on which you base your entire email marketing services. It can help you increase your email deliverability and reduce the chances of getting your emails flagged as spam.

Use a Dedicated IP Address:

When it comes to the internet connection for email marketing services, your IP is your ID card, everyone has to have one. Many leading (email service providers)ESPs offer their users shared IP, where several users share the same IP to send their emails. The problem with this is that all the people who share the IP will get flagged if even just one of them is a spammer.

Luckily, all advanced ESPs offer dedicated IP service, as part of their email marketing services, to its users at a small price.

It’s quite critical to highlight the fact that you need to send lots of emails for this to be appropriate. When you use a dedicated IP, but you don’t send a lot of emails on a consistent basis, then it negatively impacts your deliverability as it will be hard to be considered a spam-free, trustworthy sender.

Irrespective of your email marketing services provider, you need to warm-up your new dedicated IPs before you can reap into its full benefits. IP warm-up is a standard practice to ensure you get the highest email deliverability on your email marketing campaigns.

Additionally, you need to set-up (reverse domain name system) rDNS so that the  ISPs can know that you’re using that IP to send your emails. You can even have different dedicated IPs for different types of email, like separate IPs for marketing and promotional emails, and separate IPs for transactional emails.

Sign Up for ISP Feedback Loops:

A feedback loop, commonly referred to as FBL, is an email marketing services feature that ISPs offer to organizations that want a report of the total number of complaints received.

You can easily get flagged as a spammer and see your deliverability rates go down if your recipients are telling their ISPs that your emails are spam.

Feedback loops are very helpful for email senders to get a better sense of the way their subscribers perceive their emails and resolve any critical situation that arises. For example, by unsubscribing those people who flag their emails as spam.

Image Courtesy: ActOn

Maintain Your Reputation With Your List and Your ISP:

When it comes to email marketing services, your reputation is the key element that defines whether you’re treated as a “spammy” email marketer or not.

Reputation refers to a set of metrics that are directly related to your email sending practices email list building practices.

As a rule of thumb, the higher your reputation, the higher are your delivery rates. On the other hand, senders with a poor reputation get blocked at the gateway or their emails end up in the spam folder instead of the inbox.

Image courtesy: ReturnPath

The following are five attributes of high-reputation accounts:

Few Complaints:

As mentioned above, when recipients mark your emails as spam or junk, it is considered as a complaint. The more complaint you get, the worse your reputation gets and lower are your email delivery rates.

When the ISPs see that there are a significant number of complaints, they can block you without you even realizing it.

Your goal should be to keep your complaint rates as low as possible and zero if possible to be seen as one of the top email marketing companies.

Authenticate Your Emails:

For your email streams, authentication is an “ID check”. Basically, email authentication is a way to prove to your ISP that your email hasn’t been hacked by validating that the email is actually from you and not from any spammer trying to impersonate you.

As of now, there are three main email authentication methods, each one validating different aspects of the complete email marketing services process.

  • Sender Policy Framework (SPF): It allows senders to define the IP addresses allowed to send emails from a particular domain.
  • Domain Keys Identified Mail (DKIM): It provides an encryption key and digital signature that verifies that an email message was not faked or altered on its way.
  • Domain Message Authentication Reporting & Conformance (DMARC): It unifies the SPF and DKIM authentication mechanisms into a common framework. It also allows you to declare how you’d like your emails to be handled when they fail an authorization test.

Another email authentication process of email marketing services is Brand Indicators for Message Identification (BIMI) which is in the beta stage. BIMI is a text record that lives on your servers and works right alongside SPF, DMARC, and DKIM to signal to email clients that you are actually you.

However, the process of authenticating your emails doesn’t guarantee that your email will be delivered to your recipient’s inbox. But it helps you a lot to differentiate your organization from spammers.

Image Courtesy: EmailonAcid

Quality Email Format:

You probably have heard many marketers and brands say “content is king”, that applies to email marketing services as well. The better the content, the lower the chances that your email will be flagged as spam.

While the content is very important part of an email marketing service, your email should also be formatted in such a way that it will make your recipients actually want to receive it and even respond to it. A simple, clear design is usually all it takes for most recipients; after all, you want them to see the content of your email.

Moderate Volume:

High-volume senders are always suspicious and risk a potential red flag from both the recipients and the ISPs.

However, big brands like e-commerce retail giants like Amazon, and Target, usually send emails on a daily basis, and sometimes even twice a day. And this doesn’t pose a problem for them as they are consistent with their sending volume. The problem begins when an organization that usually send 150,000 total emails every month increases their sending volume by 4x in a month and then goes back to their previous sending volume.

Since the ISPs take consistency into consideration, so ensure that you always keep a steady email volume and avoid spiking your email sending volumes for no reason. And when you want to increase your volume, do it gradually over a period of time.

Low Bounce Rates:

Sometimes people give out disposable or incorrect email addresses to receive freebies and resources, and in some cases, their email address might even cease to exist when they stopped working at a company.

In such a scenario, the sender will receive a “hard bounce” for every recipient with an incorrect email address.

While it’s only natural, your high bounce rates may indicate that you purchased the email list.

And when any of your subscribers change their email address, you should remove them from your email list as soon as possible. This will keep the health of your email list high and you will get lower bounce rates on your email campaigns as well.

No Blacklisting:

Throughout the world, ISPs have a list of spammers whose emails are completely blocked or delivered directly to their recipient’s spam folder. These are commonly known as blacklists.

And if you get flagged as a spammer enough times, that is, if your sender reputation gets bad enough, you can easily end up on these lists, which will then get you blocked by many ISPs. This simply means that your emails will get blocked before they land in your recipient’s inbox. Some of the popular blacklists include SpamCop, MailBlacklist and SpamHaus.

While the chances of this happening to any marketer abiding by CAN-SPAM and following best practices are very low, you need to be fully aware of the existence of these lists and try to keep yourself off of them by all means. And if you’re not sure if your organization is already on one or more than one of them, you can use any of the tools to check, most of these tools are free. And one such tool that is free is “MX toolbox”.

The good news for you is that if properly follow the advice laid out in this blog, you probably will not make it on any of these lists anyway, and you’ll safe.


Email deliverability is a complex, technical aspect of email marketing services that marketers must contend with and is quite hard to master. As a marketer, it is your responsibility to ensure that your organization not just behaves, but is considered an ethical sender based on your email marketing sending practices and strategies.

For beginners, ensure that you have a strong email infrastructure that could easily sustain your email sending volumes. After that, you need to take good care of your reputation by using user-friendly, responsible, and spam-free email practices. Finally, you need to keep your account safe by authenticating your account and also the emails that go out from it.

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