• Technology

How to Improve Your Email Deliverability: Essential Practices for Success

  • Liza Pylypenko
  • 11 min read
How to Improve Your Email Deliverability: Essential Practices for Success


Email deliverability is a measure of how successful a marketing or transactional email is in reaching the intended recipient's inbox. It is an important metric to track, as it directly impacts the success of campaigns, both in terms of revenue and ROI. The good news is that there are several practices that can be implemented to improve email deliverability.

In this blog, we’ll explore the key practices, tools, and services that can be used to ensure that emails reach the intended recipients.

What is Email Deliverability?

Email deliverability is the measure of how successful a marketing or transactional email is in reaching its intended recipient's inbox. It’s the percentage of emails sent that make it past the various filters, blocks, and other obstacles that might prevent an email from being delivered. In other words, it’s the rate at which emails are delivered to the inbox, as opposed to the spam folder, junk mail, or other areas of the email system.

At its core, email deliverability is about making sure that the message reaches the intended recipient. When email deliverability is high, it means that they are able to reach the audience more effectively and efficiently, which can help improve engagement, build trust, and increase revenue.

However, email deliverability can be challenging to achieve. Many factors can affect it, including email content, sender reputation, IP reputation, and the recipient’s email server.

Factors Affecting Email Deliverability

Having low email deliverability can be expensive, meaning a business's messages may not make it to their customers' inboxes and instead be diverted to the spam folder or blocked entirely. Despite this, the placement of emails in an inbox is determined by seven components that can be managed, either directly or indirectly, by the business. We will go through each one in turn.

Sender Reputation

Internet Service Providers (ISPs) assign a "reputation score" to any organization that sends out emails. This is a very significant element of email deliverability, the higher the score, the more likely it is that the emails sent will be directed to the recipient's inbox instead of their spam folder, or in some cases, rejected outright.

Each ISP will decide which components to take into account to determine the sender's reputation, and the weight these components will have. It is also possible for a sender to have different scores with different ISPs. Likewise, if a sender has multiple domain names and sends emails from different IP addresses, each one will have its reputation score. \

Sender Reputation

IP Reputation

When internet service providers (ISPs) survey the web to assess a given IP address's safety rating, they will rapidly decide whether the users from that address are conducting themselves in the interest of good or bad.

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Having a reliable IP standing ensures the ISP recognizes that the IP address is trustworthy, unlike those of robots, fraudsters, or cybercriminals. If activities display unapproved browsing behavior, your IP address could be flagged.

In simple terms, if you are an email marketer, you ought to do all that you can to make IP standing as perfect as possible (and, of course, evade any conduct that could be considered suspicious and get you on the blacklist).


You may find it peculiar, but the quality of email content plays a role in the successful deliverability of messages. Poor content, inadequate designs, and unresponsive newsletter layouts can all negatively affect deliverability.

When deciding the security of a message, both email service providers, internet service providers, and spam filters all search for the same indicators.

When crafting a message, it is important to be mindful of the language used. Words which could be construed as negative or spam-like could be detrimental and cause your message to be diverted to the spam folder, so caution is advised.

When composing a message, it is significant to be mindful of the number of links used. If too many links are used, spam filters, ISPs, and ESPs may recognize it as a potential threat. Therefore, it is best to limit the number of links to one.

In conclusion, internet service providers, email service providers, and anti-spam filters take into consideration the length of the content in your email message. The optimal length for emails has been determined to be 500 characters. Anything beyond this may be regarded as suspicious by the system, while a message that is too brief could be diverted to the spam folder.

Key Practices to Improve Email Deliverability

Although online messaging and other forms of digital communication have been developed, email remains the most favored form of correspondence for commercial dealings.

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According to recent figures, an incredible 306.4 billion emails are transmitted daily. This is why 81% of small to medium businesses depend on email as their primary way of connecting with their customers.

However, the issue of email deliverability must be taken into account. Half of the 306.4 billion sent emails end up in spam folders, meaning that 50% of emails sent never make it to their intended recipients. This can have a detrimental effect on sales and marketing efforts, leading to a dip in productivity and, consequently, a decrease in revenue.

There are some key practices you can implement to improve your email deliverability. These include:

Optimizing Your Email Content

The email text is of utmost importance when it comes to getting your message to the desired recipient's inbox; consequently, to ensure excellent email deliverability, it is essential to adhere to the best practices described below.


Recipients will be able to see the subject line of an email as soon as it is received; 69% of the time, an email is marked as spam simply due to what the subject line reads.

Algorithmic filters or the recipient can both lead to emails with spammy keywords or irrelevant subject lines being sent to the spam folder. Therefore, spam filters effectively do the same job.

Ultimately, this will affect the ability of your emails to reach their intended destination.

Hint: Consider how an email signature can help improve email deliverability by adding an extra layer of authenticity to your emails. Additionally, an e-signature can also be used for branding and marketing purposes.

Words that elicit a spam response

It is essential to limit the use of words that are indicative of spam in both the subject line and the contents of the email.

The algorithms employed by different email service providers are constantly being revised to incorporate the most up-to-date list of potentially spammy keywords. If even one of these words is used in an email, it can significantly reduce the chance of it being delivered. So it's worth thinking about discovering words and phrases which can help optimize email deliverability.

Text and HTML code

Assuming you're looking to get the best conversion rate, utilizing visual content is the way to go, though it could adversely affect your email deliverability.

Maintaining a 60:40 ratio between text and HTML in emails is the best way to ensure that the message is not too spammy, while still providing a pleasant viewing experience for the reader.

Authenticating Your Emails

Verifying your email address is like giving it a driver's license to proceed on the path to the receiver. There are four distinct kinds of authentications required to transmit mass emails without preventing your email account and going directly to the recipient's inbox.

SPF (Sender Policy Framework) creates an entry in your DNS (Domain Name System) which provides a list of servers approved to dispatch emails in the name of a domain.

The record also stipulates how recipients should handle emails that are sent from unauthorized servers. Whenever a sender sends an email from an SPF-verified domain, the recipient's ESP inspects the SPF authentication and grants permission to the sender's domain.

Tips for improving email deliverability

DKIM (Domain Keys Identified Mail) is a method used to detect email spoofing, which involves adding an identical digital signature to your Domain Name System (DNS) records.

This helps the sender's email service provider (ESP) to discern if the email has been sent from an approved source. Implementing DKIM records into your DNS can reduce the likelihood of being subjected to email scams, as well as improve the productivity of your emails.

DMARC (Domain-based Message Authentication, Reporting & Conformance) is another authentication process, although not mandatory, which is beneficial for email deliverability. It employs SPF and DKIM records to demonstrate to the recipient's ESP that the email is not related to any fraudulent activity.

Furthermore, when Internet service providers (ISPs) block certain IP addresses or domain servers, the DMARC records act as an intervention to ensure the email is successfully sent.

**TLS **is a type of protocol that functions to give security to the data transferred between two entities.

It prevents the data from being accessed by strangers and cyber criminals to ensure that the information stays only with the sender and receiver.

Employing a custom domain is a way to boost email deliverability.

Tracking links in the email body also has the potential to send your emails to the spam folder, as email service providers usually blacklist the tracking links.

Using a custom domain substitutes the original tracking domain with your tailored domain, which is secure to use and not banned by any email service providers.

Monitoring Your Email Reputation

A sender's reputation is an evaluation given by email service providers based on a domain's score and IP address. The higher the score, the greater the probability of emails being delivered. Here we discuss how to strengthen a sender's reputation.

A new email account should not be immediately used for massive email campaigns.

It is better to start slow, sending individual emails and creating conversations first, and then incrementally increasing the number of emails sent. If many emails are sent from a new account right away, email service providers may put the account under surveillance, negatively impacting email deliverability, or even blocking the account permanently.

It is important to remain cognizant of email blacklists, which are databases that assess if a message is valid or spam.

They contain a compilation of IP addresses and domains that are thought to dispatch spam emails. There are two types of email blacklists that one should be aware of: domain-based and IP address-based.

Monitoring Your Email Reputation

The former is a list of domains that are frequently used for spam or phishing, while the latter is a list of IP addresses or networks that are oftentimes utilized to send junk mail or abusive material. It is significant to keep track of your domain and IP address as if they become blacklisted, you need to go through the process of warming up your domain and beginning anew.

To gain more information about email blacklist-checking tools, please refer to the instruments in the article.

Many email service providers give the option for those who are unsubscribing to provide feedback in the form of surveys or other forms. This creates a loop of feedback that allows the sender to stay in touch with what their users need and desire. When someone decides to opt-out, they can leave comments for the sender as to why creating a meaningful dialogue.

In the long run, this feedback loop will help with the sender's email deliverability, allowing them to keep a list of recipients that is more organized and valuable.

It is imperative to confirm the list of email addresses when sending out messages.

It is not inconceivable to acquire a list of contacts, however, some of their email addresses may be invalid or out of date. Therefore, it is always advised to use a validation tool to validate the list of recipients. Doing so will decrease the bounce rate, enhance email deliverability, and improve the sender's reputation score.

To keep your email list clean up, regularly review engagement and remove any subscribers who no longer seem interested, run your list through a validation tool, and segment your list into active and inactive subscribers.

Generally, verifying the list of contacts with a verification tool will divide them into three categories: valid, risky, and invalid.

  • Valid contacts are those that are authenticated and safe to send.
  • Risky contacts are those that exist but are not secure to send as they are not active.
  • Invalid contacts are nonexistent or expired, thus, it is not suggested to send emails to them as they will most likely bounce.

Avoiding email returns is a must.

No one enjoys having their emails returned, but unfortunately, it still happens. If a message is returned, it can mean a missed chance despite all the hard work. Moreover, if a sender has a high number of bounced emails, their domain may be placed on a blacklist and/or blocked by the email service provider.

There are two types of bounces — Hard and Soft.

  • A hard bounce is generated when the recipient's email address does not exist, it has expired, or the domain is invalid. This is a permanent bounce, which means you can never email that address and must remove it from your list of recipients.
  • A soft bounce is produced when the recipient's inbox is full, the email file size is too large, or any other temporary issue. These bounces are only temporary, but if you are unable to deliver emails to these addresses after several tries, then you need to remove them from your list.

How to Monitor and Test Email Deliverability

Once you have implemented the key practices to improve your email deliverability, it’s significant to monitor and test it. This can be done using many tools and services, such as email deliverability monitoring tools and email deliverability testing services.

Email deliverability monitoring tools are used to track your email deliverability and ensure that it remains high. These tools provide real-time insights into your email deliverability, such as open rates, click-through rates, bounce rates, and more.

Email deliverability testing services are used to test your emails before they are sent out. These services can help you identify any potential issues that could affect your email deliverability, such as broken links, missing images, or invalid HTML.

Presently, there are several resources, several of them cost-free, which allow you to build a proper email deliverability examination, check different facets of deliverability, and calculate how your emails operate:

  • Mailtrap — utilize Email Sandbox for assessing your email processes in a secure atmosphere. Inspect how emails look to a variety of customers, analyze their spam ratings, and examine if they are appropriately sent, without the danger of spamming recipients.
  • Sender Score — permits you to assess your domain status and provides its "Sender Score" for each IP address that you are identified to send out emails from. Additionally, verifies crucial authentications and applicable website certifications.
  • Mail-tester.com, Isnotspam.com, and Spamcheck by Postmark are supplementary instruments that allow users to quickly evaluate the reputation of an email address. Submitting an email address to these services will instantly generate a comprehensive report with proposals on how to enhance it.

Tools and Services to Help Improve Email Deliverability

In addition to monitoring and testing your email deliverability, many tools and services can help you improve it. B2B marketing tools can help businesses save time and money by automating tasks such as email and social media campaigns.

These include:

Email Deliverability Tools: These tools are used to monitor and track your email deliverability. They provide real-time insights into your email deliverability, such as open rates, click-through rates, bounce rates, and more.

Email Delivery Services: Email delivery services are used to ensure that emails are delivered to inboxes. These services provide features such as spam filtering, bounce management, and more.

Email Validation Services: Email validation services are used to check the validity of an email address before it is sent. This can help reduce bounce rates and improve email deliverability.

Email Marketing Platforms: Email marketing platforms provide powerful tools to help create, send, and monitor emails. These platforms also provide features to help optimize email deliverability, such as automated A/B testing. Also, use a website audit to check if email deliverability is up to par.

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It is critical to go for trustworthy tools that have a proven reputation for IP addresses and functions that fulfill business requirements.

These platforms have numerous email deliverability specialists, and they can assist in enhancing campaigns.

  • Mailtrap Email API grants developers more authority over email deliverability and enables them to immediately address any existing sending problems before they happen. Additionally, Email API boasts a Sending throughput of around 10,000 emails/second.
  • SendGrid is one of the major players in the market that specializes in both transactional emails and marketing campaigns. You can utilize their strong API to link their features with your platform. SendGrid also provides multiple tools for creating attractive and successful emails.
  • Sendinblue provides both transactional and advertising messaging and has extra features such as SMS and marketing automation.
  • Mailchimp is a great choice for constructing promotional activities and automation with its templates, drag-and-drop email creator, and analytics. Furthermore, they own Mandrill, a popular tool for sending transactional emails.
  • Lastly, Mailjet is a reasonable option for sending out transactional emails and newsletters, offering similar features.


Email deliverability is a key factor in the success of your campaigns. Achieving high email deliverability requires careful planning and implementation of the right practices and tools. By following the tips outlined in this blog, ensure that emails reach the intended recipients and improve email deliverability.

If you need help improving email deliverability, we recommend taking advantage of the various tools and services available. From email deliverability monitoring tools to email delivery services, these tools ensure that emails reach the inbox and maximize ROI.

At the end of the day, improving email deliverability is an ongoing process. Monitor email deliverability and make adjustments as needed to ensure that emails reach the intended recipients.

Liza Pylypenko

Liza Pylypenko

PR and Marketing

For the past several years, I've navigated the PR and marketing directions with a keen expertise in email infrastructure and product marketing. This journey has equipped me with strategic knowledge and inspired me to document my learnings to help foster business growth. My mission is to offer readers a comprehensive view into the intersection of performance-focused email marketing and the world of optimized email communication.

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