How to Test Email Deliverability

December 7, 2023 by
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An email that doesn’t reach its destination kinda defeats the whole purpose of email. It can be frustrating to discover your emails aren’t being sent, especially in a business setting, so knowing how to test your email deliverability is imperative. Testing your email deliverability doesn’t have to be complex or technical. It’s about taking certain steps to ensure your emails aren’t being marked as spam or getting lost in cyberspace.

A good deliverability rate means your content is seen by more people, increasing the impact of your messaging. This article will show you how to effectively test email deliverability to keep your communication clear and consistent.

What Is Email Deliverability?

Email deliverability, often a key metric in email marketing, measures the success of an email in reaching the intended recipient’s main inbox. The “main inbox” part is important, as you don’t want it to simply arrive in the spam or junk mail folder. If you are running an email marketing campaign, it is crucial to test your email deliverability. Let’s break down the essentials of email deliverability into bite-sized chunks.

The Difference Between Delivery and Deliverability

‘Email delivery’ and ’email deliverability’ may sound the same, but they are slightly different concepts. Delivery refers to whether an email has been successfully transferred to the recipient’s server. In contrast, deliverability takes this a step further by ensuring that the email has passed through various filters and barriers to land in the main inbox​​.

Factors Influencing Email Deliverability

Several factors can impact whether an email reaches the inbox or gets sidelined:

ISP Policies: Internet Service Providers have policies and filtering systems to protect users from spam, which can affect email deliverability​.

Email Content: Content filters assess the subject line, body text, and overall design of an email to determine its legitimacy​.

Sender Reputation: This is based on factors like the sender’s IP address reputation, how often they send emails, and how recipients interact with their emails​.

Bounce Rates and Spam Issues: High bounce rates and emails marked as spam by users can damage the sender’s reputation and, hence, deliverability​.

Measuring Email Deliverability

Deliverability is generally measured as a percentage—specifically, the percentage of emails accepted by the ISP and placed into the recipient’s main inbox, avoiding the spam folder​​.

Why Email Deliverability Matters

If an email doesn’t reach the inbox, all other metrics (like open rates and click-through rates) become irrelevant because the recipient may never see the email. That’s why aiming for high deliverability is critical for the success of email campaigns​.

Improving Email Deliverability

To improve deliverability, you should follow practices such as segmenting your audience, personalizing emails, maintaining a clean email list, and regularly reviewing email performance metrics​​.

How to Test Email Deliverability

Now that you know how important email deliverability is, let’s take a look at how to test and improve it.

When to Test Email Deliverability

Testing your email deliverability is pivotal to ensure your email marketing efforts are not in vain. It’s not just about avoiding the spam folder; it’s about making sure your messages engage and convert.

Pre-Campaign Testing: Before you hit ‘send’ on a new campaign, thoroughly checking them is crucial. This helps confirm that your emails have a high chance of landing where they should.

Post-Update Testing: Made changes to your email design or content? It’s time for another test. These alterations could affect how your emails are received by different email services.

Assessing Engagement Rates: Are fewer people opening your emails? A dip in engagement could mean your emails are missing the mark, and testing will help you figure out why.

Industry Benchmarks: With the average deliverability rate at about 88.9%, consistently scoring below 85% is a signal for you to look into the issue with a deliverability test.

Being strategic about testing can significantly impact the success of your email communications. You should consider testing based on a schedule and in response to performance indicators. If you notice your engagement metrics, such as open rates, click-through rates, or bounce rates, start to shift, it’s time to put your emails to the test.

Best Practices for Effective Testing

To enhance the accuracy of your email deliverability tests, take these steps:

  • Set Up a Test Email Account: It’s better to use a new, dedicated account for testing instead of your main one to avoid skewed results from your existing reputation.
  • Spread Out Across Email Services: Check how your emails perform on various platforms like Gmail, Outlook, and Yahoo to get a comprehensive understanding of deliverability across different platforms.
  • Check for Spam Indicators: Review your email content carefully for words or phrases that might trigger spam filters and adjust accordingly to avoid the inbox from flagging them.
  • Authenticate Your Emails: Ensure you have authentication measures like SPF, DKIM, and DMARC in place, as these can significantly boost your email’s chances of reaching the inbox.
  • Track Engagement Metrics: Regularly monitor how many people open your emails, click on links, and if any messages are bouncing back to measure engagement and identify any delivery issues.

Lastly, remember that open rates can vary greatly between marketing emails and transactional emails. Good open rates for marketing efforts are over 30%, while transactional emails—because they are often expected by the receiver—can have open rates as high as 80-85%.

Incorporating regular testing into your email strategy and adjusting your approach based on industry benchmarks will enhance your ability to maintain robust email deliverability.

Best Tools for Testing Email Deliverability

The best way to test email deliverability is to use a specialized tool. Each of the following tools is designed with different user needs in mind. They offer a range of features, from basic spam scoring to comprehensive deliverability analytics and expert consultation.

1. MailCheck

MailerCheck is marketed as a complete deliverability service, ideal for email marketers aiming to enhance campaign performance. It provides bulk and real-time API email verification, detailed reports, and ESP integration. Its pros are the comprehensive toolkit and the close integration with marketing platforms. However, you need a paid subscription for DMARC reporting and blocklist monitoring. 

The service is free for checking 200 emails, monitoring 2 blocklists, and reporting on 1 DMARC domain, with more extensive services starting at $10 for 1,000 credits and reputation monitoring from $125 per month​​.

2. Litmus

Litmus merges email design and testing into one platform, offering a visual email builder, deliverability checklist, and spam filter tests. It is praised for its collaborative environment and ease of use but doesn’t provide email verification services.

Starting at $99 per month, it’s geared toward users who need design and pre-send testing in one place​​.

3. GlockApps

GlockApps offers inbox placement, blocklist monitoring, and DMARC analysis, focusing on automated email placement tests for transactional campaigns. The platform’s advantages are its flexible pay-as-you-need model and clear instructions for improving deliverability. The downside is the absence of email verification.

The service starts free for 3 email spam tests, with bundles beginning at $79 per month​​.

4. SpamCheck

SpamCheck is a no-cost tool that assigns a spam score to your email content, aiding in identifying potential issues. Its simplicity and instant results without the need for an account are positive aspects. However, it is very basic and provides limited actionable insights, making it less suitable for those serious about improving email deliverability​​.

5. Validity Everset

This email deliverability tool distinguishes itself with features like view time optimization and competitor intelligence, along with engagement analytics and subject line testing. It offers access to deliverability consultants, which can be a significant advantage.

However, its unique features, like view time optimization, have limited application, and the full suite of features comes with higher-priced plans starting at $525 per month. A more basic plan is available for $20 per month​​.

6. Netcore Email API

Netcore Email API (formerly Pepipost) positions itself as a reliable cloud-based delivery engine, particularly useful for transactional and triggered emails. It ensures high deliverability rates and is likened to a digital mail carrier, emphasizing its efficiency and reliability. With Netcore Email API, users can trust that their emails are being delivered promptly. 

The pricing is tiered based on email volume, starting at $17.5 for 150,000 emails per month, making it scalable for businesses of different sizes​​.


SMTP2GO offers an SMTP relay service that takes charge of sending your emails and ensuring they are not marked as spam. It provides detailed analytics on email interactions and automates domain authentications, such as SPF and DKIM. This service is particularly beneficial for those who need to send large volumes of email and seek insights into email performance. 

The Starter plan begins at $15/month for 40,000 emails, with more features available in higher-priced plans​​.

8. Constant Contact

Constant Contact is not just an email marketing tool; it also provides a suite of deliverability features essential for small businesses and nonprofits. These features include real-time account reputation monitoring, automated list cleaning, and feedback analysis, which are crucial for maintaining a strong sender reputation.

Prices start at $12/month for the Lite package, with more comprehensive plans available for users who need more advanced features​​.

9. Folderly

Folderly stands out with its AI-driven approach to ensure email deliverability. It assesses your email placement and domain health swiftly upon connecting to your inbox and provides a domain score that offers a clear overview of your email performance. It boasts a claimed 100% deliverability rate and integrates with most email service providers. 

Folderly is a tool for those needing a comprehensive solution, with plans starting at $200 per monthly mailbox​​.

10. Mxtoolbox

The last tool on the list is a comprehensive suite offering a variety of tools that cover different aspects of email deliverability. With features like Blacklist Check, DMARC Lookup, and Spam Analyzer, it caters to users who need to ensure their domain and IP are not blacklisted, which could severely impact email deliverability.

While Mxtoolbox offers free blacklist monitoring, more advanced features are available in their subscription plans starting at $129/month​​.

Why Is Email Deliverability Important to Test?

Testing email deliverability is a critical aspect of any email marketing strategy, and understanding why it’s important requires a detailed explanation:

Visibility and Reach

The primary purpose of email marketing is to reach potential customers. If emails fail to make it to the inbox, they are invisible to the target audience, and their message remains unseen. Visibility is at the core of email marketing; without it, the effort put into crafting the message is in vain​.

Sender and Domain Reputation

Deliverability testing plays a significant role in maintaining the sender’s reputation. ISPs keep track of how recipients interact with an email. A high rate of engagement can enhance the sender’s reputation, while being marked as spam can damage it.

Moreover, if you’re using a free service or a domain that has a poor reputation, this could negatively influence whether your emails make it to the inbox or get filtered out as spam​.

Business Impact

The effectiveness of an email marketing campaign is contingent on emails being opened and read. If emails are delivered to the spam folder, the potential for business engagement and revenue is lost. Since email marketing often yields a high return on investment, the importance of deliverability is directly linked to the financial bottom line of a business​.

Email List Health

Regular deliverability testing helps in maintaining a clean email list. This includes verifying that the email addresses are correct and that the messages sent are not being automatically marked as spam. A clean list has a lower rate of bouncebacks, which, in turn, positively affects the sender’s reputation​.

Adaptation to Changing Filters

ISPs constantly update their spam filters to protect users from unwanted email. Testing deliverability helps ensure that your emails adapt to these changes and continue to reach inboxes. This is vital for long-term email marketing success, as it allows businesses to adjust their strategies in response to the evolving landscape of email filtering technologies​.

Ensure Your Emails Reach Their Destination

In summary, the importance of testing email deliverability cannot be overstated. It is a crucial step in ensuring that your meticulously crafted emails reach their intended destination—the inbox of your audience. By implementing regular testing, businesses can safeguard their sender reputation, optimize engagement rates, and ultimately drive conversions.

With the right tools and practices, you can turn email marketing into a powerful asset for your business. Whether you’re a seasoned marketer or just starting, prioritizing email deliverability testing is a wise and essential strategy for any digital marketing plan.


About The Author

Mike Yon

Mike is the Co-Owner of Growth List.

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