Email deliverability: How to sidestep spam

According to MailUp, between 20 and 25% of emails sent go straight into the recipient’s spam filter. This has massive implications for your ability to successfully reach your customers and achieve your business goals.

But what is deliverability, how can you assess it and how do you create a healthy deliverability? 

What is deliverability?

Deliverability is not the same as delivery rate – the two are separate concepts which must be monitored and dealt with in different ways.

Delivery rate refers to the number of emails that are accepted by the ISP or the emails which do not bounce. Emails typically (though not uniquely) bounce due to external factors such as unresponsive servers, full inboxes or deleted email addresses.

Deliverability refers to where a delivered email lands — whether in a recipient’s inbox or spam — after the ISP (Internet Service Provider) has accepted it. Deliverability is determined by your sending domain’s arrangement and reputation, which means the power is in your hands. 

To reach your customers, you need a strong deliverability rate. Following the best practices below will help ensure that your emails reach recipients’ inboxes and not their spam filters.

Best practices for healthy deliverability

Your reputation as a sender is determined by several different factors, including your domains and IP addresses, where you host images, the reputations of embedded URLs and, of course, the content of your email.

With all these factors and more, ensure that you are creating the strongest possible deliverability rate by taking the following measures:

Warm up new domains — When switching to a new domain, it is important to prepare it before executing your first campaign. Over several weeks, send a few emails manually from and to the domain, slowly increasing the send-out volume. This will show the ISPs that you are not a spam sender. 

Grow your email list organically — Always build your email lists on genuine interest. Buying contact lists will result in you sending communications to many uninterested recipients, leading to high rates of unopened emails, spam listings or unsubscribes. This will damage your domain reputation and land your emails in spam, out of view from your interested customers.

Be personal — If you send irrelevant emails, recipients will not engage with your content. Personalisation is key to sending relevant emails to everyone on your list.

Be mindful of where you host images — Some omnichannel marketing software platforms like Agillic have their own asset manager where you can host images safely. However, if you choose to host images on an external content delivery network, be sure to assess its reputation, as a poor one will affect deliverability. 

Send regularly —Send your communications consistently, as erratic sending behaviour can trigger warnings for ISPs and reduce trust in your domain. However, if you send too much, you could risk spamming your recipients – leading to fewer opens and more spam listings and unsubscribes.

Monitor engagement rates and review your email list — If your engagement rate is low, ISPs will increasingly place emails from your domain into spam. Similarly, if your email list has numerous inactive participants and high bounce rates, it triggers negative feedback to ESPs, reducing your deliverability.

Make it easy to unsubscribe — Make it easy for recipients to correctly unsubscribe from your emails. Otherwise, recipients may mark as spam, which will harm your deliverability rate. 

How to assess email deliverability health

How can you tell if these best practices are improving your email deliverability?

It can be difficult to assess deliverability health, as analytic tools categorise emails as “delivered” without specifying where they were delivered to. ESPs (Email Service Providers) provide few insights, and it is difficult to contact ISPs. For this reason, many marketers only notice poor deliverability when their campaign performance drops.

However, there are ways to obtain insights into your deliverability rate.

One way is to review the open rates for one campaign across multiple ISPs, which will help you identify any deliverability problems with a particular ISP. If you identify an ISP with lower open rates than the others, analyse open rates for that provider across multiple campaigns.

This will help you identify when the problem started, so you can analyse the relevant campaigns and determine which factors may have contributed. 

You can also use third-party tools, such as Google Postmaster Tools, to provide insights into your spam complaint rates, domain reputation and more.

Remember that domain reputation will follow you even if you switch marketing platforms. High spam reports and unsubscribe rates will continue to plague you until you either change your email send-out practices or switch domains.

However, if you stick to these best practices, your deliverability will improve over time, enabling you to reach your customers – and your marketing goals.