How to improve the deliverability of your emails

March 11th, 2019

How to improve the deliverability of your emails

Spam email, sometimes referred to as junk mail, is an email that has been sent to a recipient without their permission. In 2018, a study conducted by suggested that as much as 90% of email traffic is spam. With this high volume in mind, email providers are cracking down. Spam filters have been put in place by email providers to stop unwanted emails reaching your inbox. These filters are not 100% accurate and genuine emails can sometimes make their way to the spam folder. If you emails you send have low open rates or a lot of your emails bounce back, this could be why. In this blog post we have put together some useful information to help you identify what might be considered spam and how you can improve email deliverability.

How Is Spam Identified?

The detection of spam by email providers is highly sophisticated. The filtering process is based on many factors. These factors include the email's content, sender reputation, technical factors and blacklisting history. Spam filters score each factor according to their relative importance. Email providers then decide if they should permit an email to reach the recipient's inbox, go directly to their spam folder or bounce back to the sender.

The Content Factor - The content within the email is perhaps the most clear and humanly understandable way that filters identify spam. Certain words can act as indicators to help determine if an email is spam. Things like 'Sale now on', 'Limited Time Offer' or '£100 OFF' are the sort of terms that might increase the content spam score. Spam filters also look at how natural the content is, for example, the ratios of text to images and the number of links. If the vast majority of genuine emails contain one or two links and your email contains 10, this might increase the spam score for the content.

The Reputation Factor - When you send an email, your email address and your service provider will have a reputation score. This score is based on the quality of the emails sent previously from the email address, the email domain and the server that it is sent from. The reputation is also affected by how many times recipients clicked to mark emails as spam. Therefore, if you send an email and a high level of recipients mark it as spam, future emails will have a lower deliverability rate as the recipient's email provider will assign it a higher spam score.

The Technical Factor - One of the most common things spammers do is spoof email domains, this means that they attempt to make their email look like it has come from a trusted sender. For example, you might receive an email which looks like it has come from Amazon but in fact it's actually spam. There are technical methods that domains can use to protect themselves from this kind of spoofing, this enables spam filters to identify these emails and reject them. Sometimes genuine email senders haven't configure their domains correctly and so their emails can look more like spam than they would if the domain was configured correctly. One method to prove the origin of an email is legitimate is adding what's called an SPF record to the domain. This record contains a list of the services that are allowed to send emails with this domain in it. When an email is received by a recipient, the recipient's email provider can check the origin of the email and cross reference with the SPF record. If the email appears to be sent from a service not listed, the email will receive a high spam score. Essentially the objective of this and similar methods is to help prove that the emails are coming from the correct sender for that domain.

Blacklist Factor - When a given email service sends emails which are persistently marked as spam, the details of these servers can end up on a blacklist. If an email is received and the origin server is on one of these lists, the email will receive a high spam score. The black lists tend to relate more to the sender's email service than a specific email address or domain. For this reason, all users of that email service will be impacted by that service being blacklisted regardless of if you were the user which caused the blacklisting in the first place.

How to Improve the Deliverability of Your Emails?

There are a few things you can do to help improve the deliverability of your emails. We have outlined below a few tips to help get you started.

Quality - You can improve deliverability by ensuring that the emails you send are of good quality and genuine interest to the recipients. If you succeed in beating automated spam filter but the email you are send out is spam, the user is going to mark it as spam. The objective is not just to get an email into the user's inbox but for them to act positively to it.

Configured Domain - Ensure your domain is correctly configured for the email provider you are using. You should be able to ask your provider what's the best way to configure your domain to work with their services. Where possible add SPF and DKIM records to your domain.

Specialist Services - If you send a lot of marketing emails, you should use a specialist email sending service such as Mailchimp. These services work hard to ensure they have good reputations with other service providers meaning that their high send volumes will not appear out of the ordinary. They also employ measure to make sure that other users of their service do not damage their sending reputation. These services often have excellent reporting enabling you to see how effective your emails are and also help you to remove users from your lists who do not want to receive your email.

Removing Unwanted Recipients - As well as allowing people to easily remove themselves from your email lists, we advise actively managing your list yourself. You should remove any users who potentially don't want to receive your emails. By doing this you avoid recipients marking your email as spam and potentially causing those who are interested to not receive your emails in the future because of the reputation damage.

Test Your Email - Finally test your emails. There are many services you can send your emails to that will report on the factors outlined above and more. Running your email through one of these services can often provide very easy fixes. This could dramatically transform your email's deliverability. is one such service which we find very useful.

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