A crash course on Email Deliverability for marketers

The main objective of every marketer’s email campaign is to get their audience to engage with their well-thought-out, meticulously planned and beautifully designed emails. But what happens when your audience doesn’t receive these emails?

Image Source

Email deliverability is the measure of your emails that reach the inboxes of your subscribers. Most marketers assume that this measure is dependent on factors beyond their control. They rely solely on their Email Service Provider(ESP) to fix or improve them. But there’s a lot that goes behind the scenes into delivering your email campaigns, once you click that ‘Send’ button from your email marketing tool.

This post will help you understand the basics of email deliverability, its key components, and some of the best practices that you can follow to improve your deliverability rates.

Email deliverability vs. Email delivery rate

Before we dig more into the subject, there’s one other metric that is often used interchangeably with deliverability, namely, delivery. Email delivery rate is the percentage of emails that have been successfully sent to your subscribers’ mail servers and have not bounced back. 

There are two types of bounces – a hard bounce, and a soft bounce. A hard bounce may occur when your subscriber email addresses are invalid, or if their mail servers have blocked your IP, or when their domain doesn’t exist. Soft bounces happen when there is an issue with your subscribers’ mailboxes or mail servers.

Image Source

Email deliverability rate, on the other hand, is the percentage of emails that have actually landed on your subscribers’ inboxes. In some cases, based on your subscribers’ preferences and filters, your emails may reach the spam folder or any other folders on their mailbox. (eg. under the ‘Promotional’ tab in case of Gmail)

So if you are wondering why your delivery rates are plummeting, you may have to take a very hard look at your email list. If deliverability is your problem, well, you should probably continue reading to know what you should do next 😉

Key components of email deliverability

There are four significant factors in play when it comes to email deliverability. They include:

  1. Reputation

Reputation or sender reputation is a metric or a score that an internet service provider(ISP) or an ESP assigns to your domain and the IP address(es) via which you send your emails. This score depends on your email sending practices. Your sender reputation would be high when you:

Maintain proper list hygiene: Ensure that your email lists are updated frequently. Always remove email addresses that bounce often or subscribers who have been inactive for more than three months. And never purchase email lists that tarnish your sender reputation.

Send a consistent volume of emails: Always send a steady amount of emails via your ESP. Your reputation would be affected when you send emails inconsistently, or when there is a sudden surge in the volume of emails that you send.

Keep your subscribers engaged: Make sure to segment your lists and send personalized emails to your subscribers. When you send too many irrelevant emails, your subscribers mark you as spam. When your subscribers’ mailboxes recognize your email address or IP or domain as spam, there is no coming back.

Avoid spam traps and blacklists: Spam traps are basically email addresses that belong to no one. It can land in your email lists only when you adopt bad email practices like not seeking permission from your subscribers, or when you purchase lists. When you send emails to spam traps, your IP would be blacklisted by ISPs. Sometimes in spite of being diligent and adopting precautionary measures, you might still end up sending emails to spam traps and end up in blacklists. In such cases, it is advisable to get in touch with your ESP or deliverability experts to figure out a way from this tricky situation.

2. Content

Another crucial factor that affects your deliverability is the emails that you are sending out to your subscribers. There may be different campaigns that you run for which you use different email types. Whether you draft plain text or HTML emails, make sure you lookout for the following:

Spam triggers: Look out for spam trigger words in your subject lines and email copy. Some examples of spam trigger words include free, discount, etc. You can find a detailed list in this blog” How to avoid spam filters?. Mailboxes monitor your emails, and having these words on them would send them directly to the dreaded spam folder. 

Image to Text Ratio: When you add images in your emails, make sure that you follow the industry-standard image to text ratio 80: 20. This gives a better customer experience and warrants fewer complaints.

Links: Sometimes, when you include links to websites that have a low domain score or low reputation, your emails are automatically classified as spam.

HTML Markup errors: Always exercise maximum care when you intend to send HTML emails. Ensure that your HTML is formatted correctly and is devoid of any markup errors that distort your emails. And make sure that all your HTML emails are mobile-friendly.

3. Authentication

Authentication is key to boosting your emails’ deliverability. It allows your subscribers’ mailboxes to confirm that you are actually sending the emails. And not an impersonator or a fraudster for malicious purposes. Understanding authentication can get a little too technical for a marketer. Though your ESP handles most of this stuff, you still need to have an overview of what is actually happening with your emails to stay on top of your email deliverability practices.

How does authentication work?

When you send emails to your subscribers, your IP address and domain is thoroughly vetted by their mailbox providers to minimize spam. The mailbox provider checks if your IP is allowed to send emails on behalf of your domain. This is authentication. Setting up authentication is a surefire way of improving your email deliverability.

Two main frameworks are adopted universally for this authentication process – SPF and DKIM.

SPF, also known as Sender Policy Framework, is an authentication method that validates the sender’s email address. In your DNS server, your web administrator would have defined the IP addresses that can send emails on behalf of your domain. These are the SPF records. When your subscribers’ mail servers receive your email, they verify if your IP address is authorized to send emails via these records.

DKIM or DomainKeys Identified Mail verifies if the email was sent by your organization. Under this framework, there are two keys – a publicly shared one and a privately encrypted key in the header of your emails. Your recipients’ mail server decrypts the private key and compares it with the public one. If they match, your message would be passed to your subscribers’ inboxes.

Adopting both the frameworks together has been the industry standard. Authentication is vital for your emails’ deliverability. But just because you have authenticated your emails doesn’t guarantee that it will end up in your subscribers’ inboxes. Yeah, it’s twisted like that!

4. Infrastructure

Email deliverability depends on the type of infrastructure(the hardware and the software) that you use to send your emails. Unless you are a very big corporate organization, who has the time and resources to set up complex mail servers and maintain them, relying on a robust ESP would be a better alternative. Your ESP takes care of the delivery part, and you can concentrate on the above three factors to improve your deliverability rates.

Image Source

Email deliverability best practices

List Management: Managing your lists is very crucial for your deliverability rates. Never purchase email lists, grow your own from scratch. Seek permission from your subscribers to email them, and use double opt-in for confirmation. Make it easy for them to subscribe to only certain lists or to unsubscribe completely based on their preferences. 

Comply with regulations: Make sure that the emails you send, the frequency and cadence strictly adhere to privacy regulations. With laws like GDPR, and CAN-SPAM in effect, it would be a total disaster should your emails violate them. 

Use dedicated IPs: Your ESPs would provide you the option to purchase dedicated IP addresses. This is better than using a shared IP pool to send your emails. Since you have more control and visibility over the type and volume of emails you send. Once you purchase a dedicated IP for your business, make sure you warm them by slowly increasing the volume of emails that you send, rather than sending them all in one go.

Subscribe to feedback loops: Some ISPs offer a feedback loop service that notifies the email senders when their subscribers mark their emails as spam or raise a complaint against them. Your ESP would handle this, and share the information with you. You can then remove those email addresses from your list so that it doesn’t affect your email deliverability.

Constantly monitor IP and domain health: Most ISPs offer tools that help you keep a close eye on your IP and domain health. Some of the tools include Google Postmaster that provides information on sender/IP reputation, authentication rates, delivery errors, and more. Again if you are using an ESP, you need not bother about the technicalities of your IP health, as it would be handled from their end.

There would be no point in doing email marketing if your emails do not reach your subscribers. Maintaining email list hygiene and choosing a reliable ESP would go a long way in ensuring a high deliverability rate for all your email campaigns.