How To Check and Improve Email Deliverability?

ISPs struggle to verify the legitimacy of emails from unauthenticated domains, leading to a higher risk of being filtered into spam folders or blocked altogether.

This also exposes your domain to spoofing and phishing attacks.

Domain authentication mitigates these risks and ensures that your emails are not tampered with during transition, this not only increases trustworthiness but also boosts the likelihood of your emails landing in the recipient’s inbox.

Domains that incorporate authentication protocols like SPF, DKIM, and DMARC are considered to be genuine by the ISPs thus maintaining strong email deliverability and safeguarding your brand’s name.

Regularly check your sender reputation score and ensure it stays high.

This score is calculated based on traditional email metrics, including unsubscribes and spam reports. The ISPs will automatically reject emails with bad sender reputations.

Always remember that email deliverability and sender reputation go hand-in-hand and are influenced by pretty much the same factors. Hence avoid practices that negatively impact your sender’s reputation, CTR, or engagement rates.

Moreover, to effectively monitor your sender's reputation, you use tools such as Google Postmaster or Return Path.

Google Postmaster provides insights into how Gmail users interact with your emails, offering data on spam reports, domain reputation, and delivery errors. This helps you identify issues that could be affecting your deliverability.

On the other hand, Return Path offers a comprehensive view of your email performance across various ISPs, allowing you to track your sender reputation, inbox placement rates, and subscriber engagement. It also provides recommendations to improve your email marketing strategy, ensuring your emails reach the inbox and are well-received by recipients.

When recipients find your emails irrelevant or uninteresting, they are more likely to mark them as spam, or even block in some cases.

So why not keep emails concise when everyone’s busy and their inboxes are already overflowing?

Keep your email content to the point and personalize by talking about the recipients’ pain points, interests, and relevant recommendations.

Your emails should be adding value and they should not look overly promotional. If they create the impression of “too good to be true” - they will not get opened, gradually contributing to a bad sender score and deliverability.

Also, make sure you follow all email design guidelines and avoid using spam trigger words like ‘Free’ or ‘Guarantee’, excessive links, and overly promotional content to surpass spam filters.

Pro Tip: You can even ask your users to whitelist your emails by moving them to primary inbox.

How will the ISP filter know if your email and domain are trustworthy?

This is where your Sender IP address reputation plays a role. It directly and largely affects your email deliverability. One factor that alarms ISPs is an unusual spike in sending volume and you do not want to do that as it can restrict your email account.

So, make sure you are warming up your IP address, before sending out campaigns from a new email address, and slowly increase the sending volume to build a positive reputation with the ISPs or ESPs.

Even when it is not a new email address, never make a big jump in your sending volumes, always increase the number of emails or accounts you are reaching out to gradually.

Send emails to your most engaged users, then scale up to your full list.

There’s a good chance that some individuals may choose to opt out of your email services over time. It may be because they are no longer interested, receive too many emails, don’t find value, and whatnot.

Now in such scenarios, if they don't have an easy way to opt out, they are more likely going to mark you as SPAM - this will have an even worse effect on your campaigns. Also, this is against the law.

Hence, you must include a clear, one-click unsubscribe link, which supports a positive sender reputation and improves your deliverability in the long run.

This also ensures that only genuinely interested recipients remain on your list, thereby maintaining optimal email list hygiene.

Also, if you don’t want to lose a subscriber and give it a last try, try using preference centers where the subscribers can change their preferences for receiving emails.

This way, subscribers can modify their email preferences by choosing the type of emails they wish to receive and how frequently they want to receive them. Not only will this help retain subscribers, but it will also help you plan better email campaigns and increase engagement.

Harvesting email addresses through single opt-ins might seem advantageous as it is easy but can backfire as it generates high spam complaints.

Implementing a double opt-in process introduces an additional verification step that ensures subscribers are genuinely interested in your content, thereby enhancing engagement rates.

Just send a follow-up email to validate their email address or a confirmation link.

Sending an email incorporating the sender's name and your brand’s name can increase your opening rate by 45% as it builds trust and authority.

Brand Indicators for Message Identification (BIMI) boosts email deliverability by displaying a
brand’s logo alongside authenticated emails, enhancing trust and visibility. Implementing BIMI requires strong email authentication (SPF, DKIM, DMARC), a Verified Mark Certificate (VMC), and publishing a DNS record pointing to the logo.

This improves brand recognition, increases recipient trust, and prevents phishing, leading to better email engagement and higher deliverability rates.

ISPs closely monitor recipient interactions with your emails, and higher engagement rates—such as opens and clicks—signal that your content is valuable and relevant.

Regular analysis of these engagement metrics is essential for maintaining list hygiene, as it enables you to identify and remove inactive or unengaged subscribers, thereby reducing bounce rates.

This also helps you spot trends and refine your strategy accordingly.