How to improve email deliverability

Email deliverability is a measure of how your emails can successfully reach your users' inbox without bouncing or being marked as spam. If you have issues with high bounces, flagging spam filters, or low engagement, you may have email deliverability issues. 

When it comes to infrastructure Prefinery has got you covered from keeping our IPs clean, throttling to the ISPs, properly monitoring and handling bounces and spam complaints, and keeping up with industry-standard best practices and things like DKIM

We also provide you the option to set up your own custom SMTP server for your campaign if you want more control on the infrastructure aspect.

With that said, each project can be unique and may have its own requirements for its emails that may affect deliverability. Also, your sending reputation lies in how you handle communication with your users. 

If you are having issues with users receiving your emails, or would just like to optimize the delivery of your campaign's emails, here are some tips: 

Enable double opt-in

Infrastructure plays a huge role, but if you are sending email to people who don’t want or expect it, you’re going to have delivery issues. Having good sending practices is the priority to having your email get to the Inbox. 

By enabling double opt-in on your project where the user has to click a confirmation link on an email after signing up, once they opt in it can be a way for them to unknowingly tell their spam filter "I'm okay with receiving emails from this sender, or emails like this in general". They’re also less likely to report messages from your domain as spam. If messages from your domain are often reported as spam, future messages are more likely to be delivered to the spam folder (not just for that one user, but for others too). 

Not only does a confirmed opt-in protect you from erroneous signups and spambots, confirmed opt-in lists also see better results with almost every engagement metric. 

If you'd rather have double opt-in turned off, make sure that your users had recently expressed consent to joining your campaign so they expect your email and will not mistakenly mark it as spam or unsubscribe immediately as defined here: Prefinery Acceptable Use Policy

To learn more about the benefits of double opt-in, check out our guide here: What Is Double Opt-In and Why You Need It

Have a verified return-path

To be able to send Prefinery emails with your domain email address (e.g. as the sender, you'd need to get the sender address confirmed and its domain verified. 

Verifying the domain helps ensure that your sent email arrives in your user's inbox. Additionally, emails signed by your own domain will look as if they've been sent directly from you, rather than delivered by 

Domain verification requires the DKIM to be verified. A verified return-path, while optional, may also help with improving the chances of your emails getting through some recipients as it is used by receiving email domains to check for SPF alignment

To learn more about how you can fully verify your sender address domain, including a return-path, please see: How do I verify my domain?

Learn from your users

From your project dashboard, if you go to Email > Suppressions you'll find the users that either got hard bounced, unsubscribed, or submitted a spam complaint for the email you sent to them. Checking on each of these users' profiles you'll find which email was last sent to them which made them unsubscribe or file a spam complaint. 

Knowing these will give you an idea on how to better improve your emails and make sure you don't come across as spammy or unexpected to them. 

Even with all of the above, ultimately mailbox services like Gmail will never disclose their exact algorithms for what identifies an email as spam which makes sense considering how actual spammers may take advantage of such information.

If you look it up online, you'll be told ( like this help doc from Google themselves) that there are a number of factors that may cause this to happen, but there is not a known exact set of causes nor solutions - only suggestions that may help with improving your email deliverability. 

Here are some examples:

  • Always have an Unsubscribe link - While an unsubscribe link must be included in every email sent through Prefinery (all default email layouts have them in the footer), we also recommend that it be simple and easy for your recipients to find. 
  • Avoid URL shortening services to add links within your emails - Since URL shorteners are used by spammers, the URL or source IP address of the services are frequently added to block lists. Always try to use your own domain or the url of a service you know is not used by spammers.
  • Don't mismatch URLs - Ensure the URLs of your image sources and link URLs in your message match the FROM/sender email address domain you're using. 
  • Links in the body messages should be visible and easy to understand - Recipients should know where they go when they click links.
  • Subject lines should be relevant and not misleading - If your subject line makes your email look like spam, then people and the spam filters ISPs put in place to protect them will probably think that it’s spam. 
  • Don't use too many images (nor use only images) in the content - Emails with very little copy and many images, or simply composed of one large image, are popular with spammers. 
  • Avoid sending mails to the same user in bursts - If you've setup multiple emails to have the same trigger, add varying/incremental delivery delays to each as to not bombard the user with multiple emails.

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