Best Practices for Improving Your Email Deliverability

Deliverability measures the rate at which your emails get delivered. It means that your emails should be delivered to the inboxes of your recipients and not end up in spam folders (or not delivered at all).

Ruth Patel’s 2018 Deliverability Benchmark report shows that 15% of all emails don’t get delivered. So if you are sending to a list of one million subscribers, 150,000 people will never receive your message. This can significantly affect email revenue, but it can also impact customer relations by stopping transactional emails, such as order confirmations and shipping notifications, from being delivered.

Furthermore, deliverability is becoming harder, especially with actions taken by Gmail and other ISPs. Namely, email providers are getting sophisticated with measuring user engagement and behavior to impose more stringent criteria on how much of your mail gets delivered. Here are a few best practices you can follow to ensure that your email deliverability probability is high.

1. Authentication Setup

Setting up SPF, DKIM, and possibly DMARC should be your first step toward ensuring email deliverability. There are multiple authentication frameworks in place used by ISPs to determine if the email is coming from the legitimate sender. Several key infrastructures used are:

  • SPF (Sender Policy Framework) is a security measure that makes sure nobody sends emails to anyone on your behalf, so it’s very important to set this up on your Domain Name System (DNS) server.
  • DKIM (DomainKeys Identified Mail) is similar to SPF, but it’s preferable to set it up on your DNS server as an additional measure. The idea behind this key is that there are two sets—one that is unique to your domain and encrypts your signature (this happens in the header of your email), and one that is public, necessary for decrypting your signature.
  • DMARC unifies SPF and DKIM to a shared framework. It allows domain owners to declare how they would like email from that domain to be handled if it fails an authorization test.

Luckily, your email service provider will likely handle most of these authentication processes for you, or will be able to help you set them up.

Note that you need to keep up with new standards that come into play, such as BIMI (Brand Indicators for Message Identification), which safeguards the brand, application providers, and consumers from impersonation attempts.

2. Seek Permission

Whether you are capturing emails at checkout, through a site overlay, or some other source, you need to explicitly ask for permission. The more aware your contacts are that they are being opted in to your list, the lower are the chances they will automatically press that spam button or ignore your emails. Laws are being increasingly restrictive in terms of explicit permission. In general, make sure to get some form of permission before sending marketing messages to your contacts.

3. Maintain a “Clean” List

Keeping a clean list is integral to protecting your reputation in the eyes of the inbox providers, which will help maintain strong deliverability for your email program. Essentially, maintaining a clean list means following best practices, such as suppressing inactive contacts, getting deliberate opt-ins, segmenting the frequency of your sends, and sending compelling and relevant content to your list.

4. Regularly Monitor Your Deliverability

Deliverability is not an one-off action. Because so many factors are at play, you will inevitably see fluctuations in your deliverability. This is why it’s important to do regular check-ups on your current status to make sure that you catch and diagnose problems early on.

5. Throttle Your Mail

As mentioned before, throttling your mail on individual sends can help improve your deliverability. Throttling means that instead of sending all of your email at once to your list, you are sending it over a period of time (4 hours, for example), so that the ISPs are seeing a more steady trickle of emails instead of one huge spike.

6. Make Sure Your Content Is Clean

Spam trigger words, too many images, and large file sizes can all trip spam filters. Keep an eye on minimizing these spam triggers in your campaigns—most ESPs have some form of a built-in tool to help with this.

7. Never, Ever Buy a List

Just don’t do it. Ever. Trust us.

You don’t have to advertise your unsubscribe link loudly, but you need it to be clear. Not only is an unsubscribe link required by CAN-SPAM law, it can also help your deliverability. Remember, unsubscribes do not count against you, but if you make it overly difficult for your contacts to unsubscribe, they may default to the spam button instead, which will definitely hurt your deliverability.

9. Be Consistent In Your Sending

Just as consistency in business helps establish your reputation as a business person, consistency in your email sending helps solidify your sender reputation. In general, aim to be consistent in your from name, sender domain, send volume, etc.

10. Use a Private Sub-Domain

Using a private sender sub-domain, such as, can help establish your domain-level reputation. ESPs will usually provide a default sender domain if you don’t have a private sub-domain, but remember that these won’t be transferable if you ever decide to switch providers.

11. Consider Using a Dedicated IP

If you are sending a good amount of volume and have the guidance to maintain a dedicated IP, you should consider switching over. With a dedicated IP, you’ll have full control of your own sender reputation without worrying about it being tarnished by other senders’ bad practices.

In Conclusion

By following these best practices for email deliverability effectiveness, our business is sure to experience a decrease in the number of email bounces as you reach out to your audience.