Email Deliverability in 2023: the Ultimate Guide

In the war against email spam, internet service providers (ISPs) have cracked down on the ability of an email to reach a user’s inbox. This is for the users’ benefit – they can enjoy a (mostly) spam-free inbox where they only see what they’ve consented to seeing.

However, ISPs sometimes block important emails from reaching inboxes due to some small mistake on the sender’s part, which could be easily fixed, but for the moment, prevents them from reaching their audience.

In this article, I’ll guide you through the basics of email deliverability and give you some tips on what to do and what to avoid to keep your email deliverability as high as possible.

Now, first things first…

What is email deliverability?

For me to explain how to maximize your email deliverability, I need to tell you what email deliverability actually is.

In technical terms, email deliverability refers to an email’s ability to reach the inbox of its intended recipient. In other words, it’s a measure of how likely it is for an email to avoid being blocked, marked as spam, or sent to the recipient’s junk folder.

Email deliverability is a critical factor in the success of email marketing campaigns. Even if you have a well-crafted email with a strong call to action, it won’t be effective if it doesn’t reach your subscribers’ inboxes. Poor email deliverability leads to low open rates, low click-through rates, and, ultimately, reduced revenue.

For reference, good email deliverability should be between 85% and 95%.

The issue with this is that, according to Influencer Marketing Hub, only 79.6% of legitimate emails reach their final destination.

So, on average, even if your emails aren’t spam and are completely genuine, you might not be able to reach one out of every five people you send emails to.

If your email deliverability is lower than 85%, like the average, keep reading while considering the influencing factors below, and see if you can improve in any area.

What impacts email deliverability?

1. Sender Reputation

Sender reputation is the overall score ISPs give your domain and IP address. ISPs use sender reputation to determine whether to deliver your email to the inbox, or the spam folder, or reject it altogether.

Your sender reputation is based on several factors, including email-sending practices, engagement rates, and feedback loop complaints. The higher your sender reputation score, the more likely your emails will reach your subscribers’ inboxes.

Here are some tips to improve your sender reputation:

  • Use a dedicated IP address for your email campaigns. Shared IPs can be affected by other users’ sending habits, leading to a lower sender reputation score.
  • Only send emails to subscribers who have opted-in to receive them. Sending unsolicited emails can result in a high number of spam complaints, which can hurt your sender reputation.
  • Monitor your email engagement rates, such as open and click-through rates. ISPs use these metrics to determine the relevance and value of your emails.
  • Make it easy for subscribers to unsubscribe from your email list. If someone wants to stop receiving your emails but can’t unsubscribe, they may mark your emails as spam.

2. Email Authentication

Email authentication is the process of verifying the email sender’s identity to prevent email spoofing, phishing, and other email-related fraud. Email authentication protocols, such as SPF, DKIM, and DMARC, are essential for email deliverability and help prevent your emails from being marked as spam.

Here’s a brief overview of each authentication protocol:

  • Sender Policy Framework (SPF): SPF allows you to specify which IP addresses are authorized to send emails from your domain. When an ISP receives an email from your domain, it checks the SPF record to ensure it came from an authorized IP address.
  • DomainKeys Identified Mail (DKIM): DKIM adds a digital signature to your emails, which verifies that the email came from an authorized sender and has not been tampered with.
  • Domain-based Message Authentication, Reporting, and Conformance (DMARC): DMARC is an email authentication protocol that builds upon SPF and DKIM. It allows you to set policies for how ISPs handle emails failing authentication checks.

Implementing these authentication protocols can improve your email deliverability and prevent your emails from being marked as spam. If you’re unsure how to implement these protocols, consult with an email deliverability expert or your email service provider.

3. Email Content and Design

The content and design of your emails play a significant role in whether your emails will be marked as spam or delivered to your subscribers’ inboxes. Here are some best practices for email content and design:

  • Keep your subject lines short and avoid using spam trigger words such as “free,” “urgent,” or “act now”.
  • Use a clear and recognizable “From” name and email address. This helps build trust with your subscribers and can prevent your emails from being marked as spam.
  • Avoid using too many images in your emails, which can trigger spam filters.
  • Make sure your email content is relevant and valuable to your subscribers. If your subscribers find your emails helpful, they’re more likely to engage with them, which can improve your email deliverability.
  • Use a responsive email design that adapts to different screen sizes and devices. This can improve the user experience and make your emails more engaging.

4. List Hygiene

List hygiene refers to the process of keeping your email list clean and up-to-date. This involves regularly removing inactive subscribers, updating contact information, and removing email addresses that bounce back.

Having a clean email list can improve your email engagement rates, reduce bounce rates, and prevent your emails from being marked as spam. Here are some tips for maintaining a clean email list:

  • Remove inactive subscribers who haven’t engaged with your emails in a long time. A large number of inactive subscribers can negatively impact your engagement rates and increase your risk of being marked as spam.
  • Regularly update your contact information, including email addresses, to ensure that your emails reach their intended recipients.
  • Remove email addresses that bounce back. If an email address bounces back, it could indicate that it is no longer valid or the recipient’s mailbox is full.
  • Segment your email list based on subscriber behavior, demographics, or interests. This can help you send targeted and relevant emails to your subscribers, improving your email engagement rates and preventing your emails from being marked as spam.

5. Email Frequency and Timing

The frequency and timing of your emails can impact your email engagement rates and deliverability. Here are some best practices for email frequency and timing:

  • Determine the optimal frequency of your emails based on your subscribers’ behavior and preferences. Sending too many emails can overwhelm your subscribers and increase the likelihood of being marked as spam. On the other hand, sending too few emails can result in low engagement rates.
  • Test different send times to determine when your subscribers are most likely to engage with your emails. For example, if you’re targeting a global audience, you may need to adjust your send times based on different time zones.
  • Consider sending automated emails, such as welcome emails, abandoned cart emails, or post-purchase follow-up emails. Automated emails can be triggered based on subscriber behavior, and they’re often highly relevant and engaging.

6. Monitor Email Deliverability

Monitoring your email deliverability is essential for ensuring your emails reach their intended recipients’ inboxes. Here are some tools and metrics to monitor your email deliverability:

  • Email service provider (ESP) reports: Most ESPs provide reports on email delivery rates, open rates, click-through rates, and bounce rates. Use these reports to monitor your email performance and identify any issues that need to be addressed.
  • Email deliverability tools: There are several third-party email deliverability tools, such as Sender Score and GlockApps, that can help you monitor your sender reputation and identify any issues with your email authentication or content.
  • Email seed testing: Seed testing involves sending test emails to different email addresses and monitoring their delivery and placement in the inbox. This can help you identify any issues with your email content or authentication that may be affecting your email deliverability.

How can I test email deliverability?

Luckily, if you have concerns about your own email deliverability, there are many free tools that you can use not only to see how your emails look in a recipient’s inbox but to test how often they make it into the inbox itself.

Here are a few tools you can use to test email deliverability:

  • Sender Score: helps you assess your domain reputation and gives a score for each IP address you’re known for sending emails from.
  • Mailtrap: allows you to use their Email Sandbox to test your email workflows in a sandbox environment, test how emails look in various clients, analyze spam scores, and test if they’re properly delivered.
  • Spamcheck: provides tools for basic reputation checks by emailing an address, then provides you with a detailed report and suggestions for improvements.

What are the best platforms for email deliverability?

From Influencer Marketing Hub, here are the top 5 email marketing platforms for email deliverability:

  1. MailerLite – 98.0%
  2. CleverReach – 96.5%
  3. Constant Contact – 90.9%
  4. ActiveCampaign – 90.2%
  5. Sendinblue – 90%


Email deliverability is essential for the success of your email campaigns. By focusing on your sender reputation, email authentication, content and design, list hygiene, email frequency and timing, and monitoring your email deliverability, you can improve your email engagement rates and prevent your emails from being marked as spam.

Email deliverability is an ongoing process requiring regular monitoring and optimization. By following these best practices, you can ensure that your emails reach their intended recipients’ inboxes and drive the desired results for your business.