8+ Best Practices to Improve Your Email Deliverability

May 08, 2023
Written by
SendGrid Team
Opinions expressed by Twilio contributors are their own

8+ Best Practices to Improve Your Email Deliverability

Looking to improve your email deliverability? You've come to the right place. We eat, sleep, and breathe email deliverability at Twilio SendGrid, and we realize it's arguably the most important metric for your email program.


Because your emails can't be opened or clicked unless they get delivered first. Deliverability rates impact everything.

Fortunately, email deliverability isn't rocket science. You just need to follow email deliverability best practices, get your ducks in a row, and be a good sender—and voila—your email deliverability will improve.

Below, we'll walk you through everything you need to know to improve email deliverability and send your email program to new heights.

What is email deliverability?

Deliverability means the rate at which emails actually make it to subscriber inboxes. Email deliverability failure is usually when an email went to the spam folder or was blocked by the ISP.

How to improve email deliverability

So, how do you make sure your email gets delivered? Luckily there are proven techniques to prevent failures and improve your email delivery rates for the long term. This guide offers an overview of the steps most businesses need to take to maximize their email deliverability:
    • Authenticate your email domain
    • Maintain proper IP allocation
    • Perfect the opt-in process
    • Write non-spammy subject lines
    • Provide a preference center
    • Keep clean lists
    • Avoid spam traps
    • Send email that people love

1. Authenticate your email domain

Impersonation is not a form of flattery in the email world–it’s one of the quickest ways to tank your sender reputation. If you are not enabling Sender Policy Framework (SPF) and Domain Keys Identified Mail (DKIM), you risk falling victim to email spoofing (somebody taking control of your email domain) and, as a result, experiencing poor delivery rates.

Authenticating your email with SPF and DKIM proves to the ISPs that you really are who you say you are and are worthy to send email. Email authentication can be tricky, so it deserves its own post. Read up on email authentication in our 101 post, so you know that you are covered.

2. Maintain proper IP allocation

As your email program continues to grow, it’s important to keep in mind that you will need the proper email infrastructure as you scale. Once you reach 25,000 daily emails, you will want to send on a dedicated IP address. And when you add a dedicated IP address, you’ll have to properly warm it up before sending to your entire list so that your gain trust with the ISPs that you are sending wanted email.
Don’t just keep adding IPs to avoid penalties. ISPs are smarter than that and they will end up blocking an entire IP pool if they suspect this is what you’re doing.
For more on how to getting your IP send-ready, download SendGrid’s How To Warm Up an IP Address.

3. Perfect the opt-in process

How you collect email addresses plays a large role in your deliverability rates. An optimized opt-in process ensures that your email list is full of engaged users. If you are sending email to people who weren’t aware or didn’t agree to receive messages from you, they will mark your emails as spam and the ISPs will think you’re spamming everyone on your list (even those on your email list that want to receive your email!).

We recommend using double opt-in which involves two verifications for the user and proves far more successful in cultivating an engaged email list. Check out our How To Grow Your Email List Guide to learn more about growing your email list the right way.

4. Write subject lines of the non-spammy variety

Your subject lines are crucial pieces of content that will ultimately determine if a user opens your emails. Although ISPs continue to become more sophisticated in their filtering systems and certain catchphrases won’t necessarily place you in the spam folder automatically, it’s wise to avoid using common spam phrases in general.

Some of these phrases include:
      • Eliminate your debt
      • Risk-free
      • FREE!!!
There is no absolute rule or words that, if avoided, will guarantee you a place in the inbox. And many legitimate emails might include the words above. But when you’re writing your subject lines, focus on the genuine value of the message without sounding pushy or salesy.

Read up more on email subject line prowess and manners by checking out our post, Email Marketing Subject Lines: Dos and Don'ts.

5. Provide a preference center

Once your recipients have agreed to receive email from you, provide a preference center so that they can decide just how frequently they want to receive email from your brand. Doing so helps put your recipients in control and helps keep them happy. This happiness generally translates to better engagement (which is noticed by the ISPs).

If you’re unsure about what or how to create a preference center, read about 3 popular and effective types of preference centers for inspiration.

6. Clean up your list regularly

Don’t let your ego get in the way of your email deliverability. The longer you keep inactive and unengaged users on your email list, the more you risk damage to your reputation and deliverability rates.

Providing a clear and easy way for your users to unsubscribe from your emails helps automate the process, but it’s also important to scrub your list on a regular basis so that your email list is healthy and only includes people who engage with your emails.

7. Avoid spam traps

Spam traps are email addresses set in place by ISPs and email community organizations to catch spammers “in the act” from sending unwanted email. If a sender ends up sending to a spam trap, it is immediately flagged and put on a deny list.

It’s extremely challenging to get yourself off a deny list, so it’s best to never end up on one in the first place. Email marketers can avoid spam traps by keeping a clean list of engaged users and to never, ever, purchase an email list of any sort.

8. Send email that people love

You have to please two parties when trying to improve your email deliverability—the ISPs and your recipients. But if you please the latter, the former will already be taken care of. ISPs protect the end-user and if they indicate they are happy, then the ISPs will be pleased with your sending and keep placing your email in the inbox.

Above all, if your recipients enjoy and derive value from your email, they will interact with your messages.

Make email deliverability a priority

Yes, open rates, click rates, design elements, and calls-to-action (CTAs) matter, too—but they should all be secondary to improving your email deliverability.

If you’re looking for more information on the email deliverability best practices above, check out our Email Deliverability Best Practices Guide which dives into inboxing stats and insights from our team of email deliverability experts.

 Email problems? Improve your email deliverability in 8 easy steps to make sure your emails stay out of the spam folder and into the inboxes.Email problems? Improve your email deliverability in 8 easy steps to make sure your emails stay out of the spam folder and into the inboxes.

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