Last updated on
March 17, 2023
On average, 306.4 billion emails are sent every year. Out of all emails, 50% go into the recipient's spam folder (techjury.net). That is, 50% of recipients never get the email as intended. For email marketers, inbox placement is critical. Successful email placement means a high email deliverability rate, while unsuccessful email placement can mean a low email deliverability rate.
Maintaining a reasonable deliverability rate is crucial because it can save the sender from being blacklisted as a spammer by the internet service provider (ISP). Apart from that, a good email deliverability rate helps keep conversion rates high. Also, low email deliverability rates are detrimental to marketing and sales efforts.
What can you do to keep your emails from ending up in the dreaded spam folder as an email marketer? What industry best practices can you use to keep your email deliverability rate high? This guide will answer all of your questions.
Email deliverability is the ability of an email to arrive in the recipient's inbox. Also, email deliverability is measured as the number of emails accepted by the internet service provider (ISP).
But it is not as simple as that. Before an email reaches a recipient, it must go through checkpoints such as content filters, spam filters, etc. These filters are set up by the various Email Service Providers (ESPs).
When an email passes through these filters, it lands in the promotional, social, primary, or spam folder. These checks are known as email reputation checks.
Email delivery is when the email reaches the recipient's server. On the other hand, email deliverability is when the sent email reaches the recipient’s inbox successfully. It is possible to have good email delivery but poor email deliverability but not the other way around. Or the email goes into the spam folder and never reaches the recipient.
The fluctuations in the email deliverability rate will determine where your email campaigns will end up. Failure to reach customers’ inboxes can reduce the performance of a marketing email. Therefore, all businesses need to keep track of this critical metric for two common reasons:
A promotional email is sent to induce the customer to open it. If 40 subscribers out of your 2000 don’t get the email, it is still a 98% deliverability rate. But the open rate might hover just above 20-40%. It means that your message is in your recipients' spam folders.
Hence, keeping track of email deliverability can help you get a holistic view of your email campaigns, like what kind of emails reach your audience more than others or if your email has anything spam-triggering. You can increase your conversion rates by keeping your email deliverability rates high.
You can avoid being marked as a spammer with high deliverability rates with spam-detecting filters set up by the various ESPs. Adhere to the industry best practices to ensure your mass email sending doesn’t get you marked as a spammer.
The average email deliverability rate in the world is 80%. An email deliverability rate upwards of 95% is considered a reasonable email deliverability rate. Reaching a 100% deliverability rate is ideal.
Still, it is unrealistic because many factors affect email deliverability, some of which are in our control and some not. The recipient's inbox is full and technical problems like authentication issues can cause your emails to bounce and increase bounce rates.
An email bounces when it fails to reach the recipient’s inbox, social tab, or spam folder, and the recipient never has a chance to see it. There are two types of email bounce: soft and hard bounce.
A soft bounce is a temporary issue in the delivery of an email. Soft bounce can occur due to a full recipient inbox, a down server, or too large an email file. During the early days of email marketing, soft bounces were a problem when inboxes could only allow a limited number of messages. Nowadays, this occurs due to a sudden increase in email sending volume.
Mail servers and ISPs watch inboxes for significant spikes in sending volume to ascertain whether or not the account is used to send spam messages. For example, if two emails were sent a week to your subscribers, and now you send two emails per day, you have increased your send volume by 14 times. Therefore, you will see an increase in your bounce rate.
A hard bounce is a permanent bounce, meaning something is wrong with the email address you are trying to reach. More often than not, it is due to an email address that doesn’t exist anymore. So, when an email address bounces, you should remove it from the list as soon as possible. By keeping your email lists clean, the email bounce rate can decrease.
But, if you don't remove dormant emails and continue getting hard bounces, it will signal to your ISP that you are not keeping your list clean, hurting your email sender reputation and email deliverability rates.
The factors that primarily affect email deliverability are email sender reputation and email authentication. Also, the content you send in your email and to whom you send it is essential for email deliverability.
Email sender reputation is a score assigned to each active organization that sends emails by an ISP. The score is calculated through an algorithm that considers many factors, such as domain reputation and IP reputation.
As the competition for the inbox increases with each passing day, ESPs tighten the criterion for a successful email placement. One out of six emails never reaches subscribers' inboxes—only those emails sent by senders having a high email sender reputation reach the subscribers’ inboxes.
Domain reputation is critical in determining the email sender's reputation score. ISPs look at various factors such as engagement, bounce rate, spam complaints, and spam traps to determine the reputation of a domain.
Domain reputation is like credit scores. The better your credit score, the better your email placement emails will be. Likewise, a negative domain reputation can relegate your emails to the spam folder, and mail service providers can block you.
Rehabilitation of domain reputation can take up to a few weeks to a few months, depending on the negative metrics such as spam trap hits, complaints, hard bounces, and low engagement rates. Moreover, you can switch to a new domain, but you must also fix your business practices to improve your domain’s reputation.
IP reputation is another essential parameter to consider when determining email sender reputation. An IP address is assigned to each and everything that is connected to the internet. Therefore, websites with no history of malicious activity or connections with domains involved in sending malware have a good reputation, while those with such records have a bad reputation.
IP reputation is critical for email marketing and businesses in general. An IP address with a positive reputation is considered a trustworthy source of information. Suppose you are a business owner, and any of your servers are hijacked and used to spread malicious content. In that case, the IP reputation will consequently suffer, and so will email deliverability.
Email authentication tells ISPs whether or not an email sent is genuine. SPFM and DKIM are the two email authentication protocols widely used. Also, TLS is another encryption protocol that has now become standard practice.
But before we explain how these email authentication protocols work, you first need to know how scammers do email spoofing.
You might have started to realize the complexity of the topic of email deliverability. But still, it is evolving and getting more complex by the day.
Spammers are always looking for new ways to abuse their email inboxes. So, it is prudent to authenticate your emails so they avoid falling into the wrong hands.
But mailbox providers are now catching up to these spammers by authenticating emails with complex email authentication protocols.
Email spoofing or phishing is a technique used to trick a person into accepting emails from someone or an entity they know or are familiar with.
An example of email spoofing is given below:
In the above example, the sender uses the display name spoofing. Display name spoofing is more straightforward to pull off than email spoofing because the spammer only needs to sign up for a free email service provider.
So, with email spoofing, scammers can impersonate your brand and send emails on your behalf. That can be highly detrimental to your business.
But fortunately, all the major email service providers are getting better at catching such scammers. They perform ID checks when receiving an email. Here’s how they do it:
Suppose that your mailbox provider receives an email from [email protected] Subsequently, your mailbox provider will do the following:
This is called authentication. But there is another thing you need to understand. You must give your email marketing service permission to send emails on your behalf.
Setting up the authentication for your email marketing service provider helps mailbox providers like Gmail and Outlook understand that you are giving consent to send emails on your behalf.
To set up email authentication, there are two ways you can do it: SPF and DKIM. Let’s look at how they work and their role in minimizing email spoofing.
Sender Policy Framework (SPF) is an email authentication protocol designed to authenticate all emails from the sender’s IP address.
Simply, SPF authenticates your ownership of the domain. When an SPF record is added to your website’s DNS, servers will verify whether you can send emails from the domain in question.
Afterward, SPF sends information to prove that the email is safe to be sent and received. The DNS record then views this information. If approved, the email is delivered to the correct folder. If not, it’s marked as spam and isn’t delivered.
DomainKeys Identified Mail (DKIM) uses encryption keys and digital signatures to validate the authenticity of emails. The primary function of DKIM is detecting and preventing phishing and email spoofing.
The domain owner publishes a cryptographic key. It is a TXT formatted record in the domain’s DNS records. When a mail server sends a message, the server generates and attaches a unique DKIM signature to the email message header. The signature is generated in a unique textual string called a “hash value” encrypted with a private key. The sender has only access to this key.
When the receiver's mail server receives the message, it runs a DNS query to search for the sender’s public key.
Moreover, unlike SPF, DKIM appears within the email and prevents the receiver from replying to malicious emails. Let’s explain this with an example.
Suppose you have a company named Article Clothing with the domain articleclothing.com. Also, you use Mailmunch to design and send emails to your customers.
If you don’t set up DKIM keys, then your emails will be signed by Mailmunch’s domain, and they will see Mailmunch in the header of the email.
Some service providers mark emails as spam if the signing and sending domains aren’t the same. In the above case, the domains will be
Signing domain: mailmunch.com
Sender domain: article clothing.com.
Unmatched domains can result in your emails going into spam or not being accepted. Hence, you must set up DKIM keys to ensure that your public key is known to the receiver DNS.
Mailmunch allows its user to set up DKIM keys and ensures high email deliverability. By checking out this article, you can learn more about setting up DKIM keys within Mailmunch.
Yes and no. Although, SPF and DKIM are necessary to set up for increasing deliverability. However, they don’t guarantee inbox placement, which depends on other factors.
When internet service providers restrict IP addresses and domain servers, DMARC comes into play and allows your email to go through using your SPF and DKIM records and assures the receiver's ESP that no malicious activities are associated with this email. Not a necessary authentication to have, like SPF and DKIM, but it is a good-to-have authentication to improve email deliverability.
Transport Layer Security (TLS) is an encryption protocol for encrypting emails while in “transit” from one secure email server to another. TLS uses Public Key Infrastructure (PKI) to encrypt messages. Therefore, making it extremely hard for hackers to intercept and read your messages. Here’s how you can know your email is TLS encrypted:
By checking the security section of your email information, you can verify whether or not your email has TLS encryption.
With a combination of symmetric cryptography and asymmetric cryptography, TLS protects your messages from being intercepted.
With symmetric cryptography, data gets encrypted using a shared secret key between the sender and the recipient. This key is usually 128 or 256 bits in length. The encrypted key then needs to be shared securely. At this point, asymmetric encryption comes into play.
Asymmetric encryption uses a pair of keys, one public and the other private. The public key is mathematically linked to the private key. This allows the recipient's public key to be used by the sender to encrypt the data they wish to send. But that data can only be decrypted with the recipient's private key.
TLS works with digital certificates, giving users an extra layer of protection. This method verifies that the senders and the receivers are those who they claim to be.
Despite innovations in cloud computing, all emails sent depend on hardware and software. Therefore, a robust mail server infrastructure must have a high email deliverability rate. Having such a mail server infrastructure is costly.
Moreover, you must be mindful of what kind of IP addresses you use to send your emails.
There are two types of IP addresses: dedicated and shared. Here’s how you can use both to meet your email deliverability requirements.
A dedicated IP address is for a single user. The IP provider will provide a unique IP address to the user and keep it separate from the local IP. Also, dedicated IP addresses are costly in comparison to shared IP addresses.
Users will always be able to use that single IP address regardless of location and purpose. Moreover, dedicated IPs are used for sending email campaigns, and email campaigns flourish when they are based on a dedicated IP address.
If your campaigns have an element of time sensitivity then you also need to have dedicated IP addresses.
As dedicated IP addresses are directly connected with the ISP, therefore, emails are delivered at lightning speeds.
If you send email campaigns of 200-300,000 emails, then a shared IP address is the way to go for you.
Moreover, if you have concerns regarding the quality and hygiene of your email lists, then shared IP addresses can help ensure deliverability.
A low open rate can also play a role in decreasing email deliverability. When an email remains unopened for a long time, it can affect your sender's reputation and, consequently, your email deliverability.
A reasonable open rate is 20%, but your sender's reputation will be minutely affected if it falls between 15% to 19%. To remedy this, you can check whether your emails are being placed in the primary inbox or the spam folder. Also, check whether the content has issues or not.
If the open rate falls below 15%, you will start seeing a lot of serious email deliverability issues. You can check for spam folder placements and email copy issues to determine the cause. Also, check whether or not your email list has inactive subscribers that need to be cleaned.
Open rates below 10% can become a big problem and can also lead to blacklisting as well. This usually happens when senders send spam emails or use purchased email lists. If you are not doing either, you can check the content you sent or update your email lists.
Emails sent to the spam folder are technically delivered but can adversely affect your sender's reputation. There are two ways your emails land in the spam folder:
Spam traps are email addresses that ISPs own to catch senders who add emails to their lists without recipient consent. Adding a spam trap to your email list can hurt your reputation and deliverability rate.
There are two types of spam traps: pristine and recycled.
Pristine spam traps are emails that are not valid and cannot opt-in to an email list. They are usually available on public websites but are hidden deep into the code of these websites. Pristine spam traps aim to identify email marketers who indulge in forbidden email marketing practices such as buying email lists.
Recycled spam traps are repurposed email addresses used to detect spammers. Recycled spam traps can be on the email list if your email list is more than one year old, you don’t email frequently, or there are invalid or typo emails.
Email service providers allow users to report emails as spam. Spam complaints give users control over what kind of emails they want to see in their inboxes. But it takes more than one user reporting to flag emails as spam!
So, if you keep sending high-quality content, your subscribers require, your deliverability rate will be high.
Moreover, you should never rent/purchase email lists or send content other than what your subscribers sign up for.
After determining the cause of the low email deliverability rate. You can use the following tips to manage low email deliverability rates.
Keeping an eye on your email deliverability rate is crucial as it can indicate how your emails are placed in your subscribers' inboxes. Also, if you are facing issues with your email deliverability, you need to test your sender's reputation to see where the problem lies.
Use the best email deliverability software and tools to test your sender's reputation.
Moreover, you can also change the email copy and see how it affects email deliverability.
You don’t need to send a huge sequence of emails to test your sender's reputation. By sending many emails, especially from a new email address, the ISPs can target your email as a spammer and, therefore, block your email forever.
So, the trick here is to start slowly and gradually. Make your email copies personalized to start conversations between you and your subscribers. Keep sending emails slowly and increase the number of emails each day.
Keeping your email account warmed up allows you to keep sender scores high and your account ready for high-volume email marketing campaigns.
After authentication, you are allowed to send bulk emails. But this is not advisable. You should keep track of the number of emails you send daily.
If you start sending emails to a long list of recipients daily, you will get blocked by some of them. Your email service provider will then begin to keep an eye on your activities and can also block your email address temporarily or permanently.
Therefore, you must keep your emails within a specified quota and make sure that you stay within the specified quota.
Make sure you stay clear of email blacklists. They are IP addresses and domains that are suspected of sending spam. Therefore, use an email blacklist-checking tool, like the MX toolbox, to check whether your IP address and the domain are in any of the global blacklists.
If your IP address or domain is blacklisted, you need to warm your account and make a fresh start.
Before you finalize your email lists, you should verify that all the addresses are genuine.
Verified email lists can decrease the bounce rate and increase your sender's reputation score. Also, checking the email lists for typos can reduce the chance of a hard bounce. Therefore, you should clear your email lists quarterly and clean out all the invalid emails before starting a new campaign.
Email service providers can redirect unsubscribers to a short survey or forms asking them to provide feedback on why they choose to unsubscribe. It is a highly effective method of keeping in touch with users’ needs.
According to research, the response rate of email surveys is approximately 24.8%. Therefore, allowing your email service provider to ask for feedback from unsubscribers is a good practice. It can help in email deliverability by keeping email lists clean.
Mailbox providers operate feedback loops to report back spam complaints to ESPs. When a subscriber hits the “Mark as spam” button, a request is sent back to ESP through the loop.
The sender then verifies that the email was indeed sent by them and unsubscribes and removes the complainant from their email list.
Hence, you need to monitor all the mailbox feedback loops. Over 20 significant mailbox feedback loops are operating.
Mailbox providers require ESPs to set up and operate an abuse-reporting mailbox. It’s an email address that can be used to forward abuse complaints.
Without an abuse-reporting mailbox, your email deliverability can suffer. Hence, you can implement it through the use of an email header.
Mailbox providers, without any feedback loops, will then forward complaints to that email.
Mailbox providers require you to have a valid MX record setup. Because otherwise, they will block your emails.
MX records are known as DNS “mail exchange.” An MX record directs email to a mail server by following the SMTP (Simple Mail Transfer Protocol.)
The content of your emails is the most critical factor in deciding whether the recipient will open your email or report it as spam, affecting email deliverability. So, think before you send the email.
If your subscribers want to hear from you about the latest phone reviews, but you send them a review of the latest blockbuster movies, then they might actually unsubscribe or worse report you.
Therefore, personalize the content before sending it to your subscribers.
Email deliverability also depends on branding. If you change your branding each time, chances are that your subscribers won’t recognize your emails and take them to be from an imposter, thus, reporting them and hurting your deliverability.
So, keep your branding consistent throughout your email campaign. Just take a look at what Nike does with its branding. Everyone’s what Nike is. That is because it doesn’t change its branding for every new email campaign.
The first thing recipients notice is the subject line. 69% of recipients report emails as spam based on the subject line. Algorithmic spam filters do the same. They search for spam trigger words and, if they find any, place your emails in the recipient's spam folder.
ESPs keep updating these spam trigger words. Therefore, email senders should update themselves regarding which words to avoid in their subject lines.
So, creating personalized and new subject lines free from spam trigger words is the way to go for increased email deliverability.
People like to be addressed personally. Emails with personalized content have a 29% higher chance of being opened by the recipient. Also, increased open rates increase email deliverability.
Due to cart abandonment, revenue of $4 trillion is lost each year. But we can recapture 65% of abandoned carts within 60 minutes of them being abandoned with a timely and personalized email.
And with a good sender reputation, your email deliverability rate will remain high, helping recapture maximum abandoned carts.
If your emails' subject lines are capital letters, this will trigger spam tracking algorithms to relegate your emails to the spam folder.
Therefore, it is necessary to make sure the formatting of your email content is correct so that it doesn’t adversely affect your email deliverability.
The use of colors is important. As visual creatures, humans tend to look for vibrant and eye-catching things. Therefore, make use of a consistent color scheme in your emails. Don’t use colors that obscure the CTA buttons or render the email unreadable. Recipients don’t like overcolored emails and report them as spam, affecting their email deliverability.
Links are needed in an email for conversion purposes. But adding too many links can land your email in the spam folder.
Also, email tracking links are mostly blacklisted by ESPs. So, if you add them, they can adversely affect your email deliverability.
Visual content is the best piece of content when it comes to conversions. Emails with visuals in them produce 650 times more engagement than compared to plain text ones. But they can hurt your email deliverability as well.
Too much HTML content in your emails can trigger a spam response. But if you only send text emails, you won’t be likely to get the conversions you expect. You need to balance the HTML and the textual content of your emails. Experts suggest that a 60:40 text-to-HTML ratio is the most suitable balance.
Giving your subscribers a clear unsubscribe option can improve your email deliverability rate. It is better to have an active email list than a dormant one. When you provide a clear unsubscribe option to your subscribers, the email lists will become cleaner when dormant subscribers unsubscribe, thus, increasing your deliverability rate.
Consistency is key. A consistent dispatch of emails from the sender can keep the email deliverability rate high and grow your email list. But there are times when businesses have to send an array of emails for marketing purposes.
But ESPs see many emails as spam, affecting the senders' email deliverability. There is no set limit for how many emails you should send, but you can slowly increase the number of emails leading up to the event.
Let’s say you send two weekly emails to your email list. But an extensive promotional campaign is coming, and you want to increase the number of emails you send to eight. You can send teaser emails about the upcoming event in such a case. The mail servers will have adjusted to the higher sending volume when the event comes.
Subscribers that don’t show any engagement, whatsoever, with the emails you send, are seriously detrimental to your email deliverability. They are the cause of high unopen rates and bounce rates. So, it is essential to remove dormant subscribers from your email lists and make your email deliverability rate rise.
In the case of a hard bounce, you should immediately take the subscriber off the email list. But in the case of low engagement or open rates, make re-engagement efforts before removing them.I’m
You don’t want to pop into people's inboxes without their consent; you might end up in the spam folder. Also, don’t buy or rent a list or use someone else’s email list. This is one of the quickest ways to decrease your deliverability rate and get blacklisted.
Although there are many places where you can get legitimate email addresses, they won’t be your legit subscribers. You have to provide an opt-in option to them for that to happen. There are two types of opt-ins:
The single opt-in option needs a visitor to take a single action to become a subscriber to the email list. You can immediately add all the leads to your list with a single opt-in and deliver the content immediately.
But with a single opt-in option, you risk gaining fake email addresses that can significantly hurt your email deliverability rate.
This is one way to go about increasing your email lists. But sometimes, the subscribers don’t know what they are providing their email addresses. This is where double opt-in comes in handy.
Double opt-in requires the prospect to take two actions before becoming a subscriber. The prospect first fills out a form and then confirms their subscription through a link known as a confirmation email.
In short, any method through which you receive an email address and confirm consent to add it is what double opt-in is.
With a double opt-in option, the leads generated are usually of high quality. Also, your campaigns can get high open rates through a double opt-in option. Moreover, no mistyped or fake emails are added to your email list.
Avoid sending emails to an email list purchased, rented, or procured in another way. It might be convenient just to buy an email list and use it, but it is illegal in some countries to send emails without the recipient’s consent.
Also, such out-for-sale lists usually contain spam traps. In short, it is better to avoid purchased email lists altogether.
You don’t want to send your emails to someone who isn’t interested in receiving them. Let’s say you email two subscribers - a seasoned marketer and a cook. If your emails are relevant to the marketer, the cook is not interested in them. He might not even open it or report it as spam.
This can happen when you don’t segment your email lists. Determining which email goes to whom can keep your sender reputation score elevated and, consequently, keep your email deliverability rate high.
Organic mobile search traffic in the USA is 63%. You can avoid losing engagement and traffic if your emails and websites are mobile-friendly. Moreover, mobile-friendly emails enjoy a click-rate and click-through rate of 30% and 15%.
Stick to a single-column display. Make sure to keep the font size to 13 or 14 points. Moreover, keep your important content and call-to-action buttons easy to find for your subscribers. So, make your emails responsive for multiple mobiles and enjoy a high deliverability rate. Ensure that you avoid using hyperlinks and avoid cluttering hyperlinks.
URL shorteners are those tools that spammers use to hide the destination of a link. They do this to hide their malicious and blocked domains and websites from users and mailbox providers alike.
Most URL shortener tools are available for free. Hence, spammers have ready access to them. So, we do advise you not to use such tools in your email campaigns.
Email deliverability is an important parameter to consider when starting an email campaign. Authenticity, mail server infrastructure, and open rates affect sender reputation and email deliverability rates. You can keep your email deliverability rates by staying away from purchased email lists, making your emails mobile-friendly, and sending high-quality content.
Moreover, provide clear unsubscribe options, remove inactive subscribers, and mind-sending limits and volumes for better deliverability.
A good email open rate should be between 17-28%. But these numbers can vary depending upon the industry you are working in.
An email sender reputation is a score that an internet service provider (ISP) provides to an organization that sends emails. The higher your sender reputation score, the more likely ISP will deliver your emails to the intended recipient.
Spam traps are email addresses used by ISP to identify senders who don’t follow email best practices.
SPF and DKIM records are located in the DNS or Domain Name Setting of your domain provider.
A voracious reader and a music lover, Ammar has been writing engaging and informative content for over 3 years for B2B and B2C markets. With a knack for writing SEO-optimized content, Ammar ensures the results speak for themselves.