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What is email deliverability: definition & solutions

by | 9 Apr 2024

Despite all its detractors, when it comes to digital communication, email remains one of the most powerful tools for businesses. Whether you use it for marketing campaigns, informational notifications or to engage your customers, email plays an important role in business communication. And transactional emails in particular. These include order confirmations, shipping notifications, password resets… Messages that are essential to your customers, maintaining their satisfaction and trust in your service. But for these emails to reach their recipients, it’s not enough that they’re well-written and relevant: the deliverability of your emails is central to the success of your communications. But what is email deliverability? Why is it important? And how can you improve it if necessary? Follow the guide!

email deliverability preview

What is email deliverability?

In simple words, the deliverability of an email is its ability to reach your recipients’ inboxes, without being blocked or landing in junk email. It’s essential for all communications. And even more so for transactional emails, since they provide important information for which time is of the essence. So, because of poor deliverability, your communications could fail to reach the recipient. The result? Customer dissatisfaction and loss of trust. Do you see the importance of this?

To spice things up, deliverability isn’t something you can take for granted. In other words, at one time or another, it can deteriorate. Whatever the cause. And this can lead to the very consequences you want to avoid: ending up on blocklists, in spam filters, or having contacts unsubscribe.

So let’s take a look at the elements that can make or break your email deliverability.

spam folder visual

Causes of good or bad deliverability

Deliverability depends on a number of factors that influence it in one way or another. These include the sender’s reputation (who you are), the content of your emails (what you send), the engagement of your recipients (do they want to receive your communications), but also the technical configurations of your emails (are your emails secure).

Sender reputation

Sender reputation is a bit like an email credit rating. It depends on how you communicate by email. We’re talking here about the quality and quantity of messages you send. ISPs (Internet Service Providers) and email services use this reputation to decide whether your message should land in the inbox or in the spam folder. So it really is essential for effective communication.

Here are a few ways to improve your reputation:

  • Clean up your email list regularly by deleting inactive or incorrect addresses.
  • Avoid using promotional language (it sounds more like spam).
  • If possible, try to maintain a constant volume of emails by sending your communications on a regular basis, and avoid peaks in email traffic.

Email content

As we said, what’s in your email has a significant impact on deliverability. And this content is as much the subject and body text as the links in your email. So if your content seems to have come straight out of spam or contains certain keywords flagged by anti-spam filters… head for the spam folder.

There are a number of tips you can apply to get your email content right:

  • Write clear, relevant subject lines.
  • Personalize emails to increase engagement.
  • Avoid using too many images or links, and always include a plain text version of your email.

Recipient engagement

Thanks to statistics and analysis of email data, it’s possible to determine whether recipients are more or less engaged with your communications. Indicators include open, click and bounce rates. With this information, ISPs can assess whether your content is legitimate and interesting.

Increasing the engagement of your contacts depends on a few relatively simple actions:

  • Segment your email list to send targeted, relevant content to your recipients.
  • Offer your recipients the option of adding your email address to their contacts or allowlisting it and be sure of a good email deliverability.
  • Use a double opt-in process to ensure that your subscribers are genuinely interested in your content and communications.

Technical configurations

The basis of good deliverability is also solid technique. We’re talking here about authentication. Because spammers often try to pretend to be someone else. And so, to make sure you don’t get caught by spam filters, you need to set up authentication protocols that ensure you are who you say you are. There are several such protocols, the best-known of which are:

SPF (Sender Policy Framework)

SPF is an email authentication protocol. It is designed to detect and prevent email address usurpation. In practice, it enables the owner of a domain to specify which mail servers are authorized to send emails on behalf of that domain. It works a bit like security at the entrance to your party, letting in only those on the guest list – and preventing others from crashing in.

DKIM (DomainKeys Identified Mail)

DKIM is an authentication method that uses cryptographic signatures to verify that an email has not been altered along the way, between sending and receiving. This enables the recipient to verify that the message has been sent and authorized by the domain owner. Which can upgrade your email deliverability of course. Think of DKIM as the (virtual) wax seal on a letter, ensuring that mail has not been opened or modified before reaching its destination.

DMARC (Domain-based Message Authentication, Reporting and Conformance)

DMARC, on the other hand, relies on SPF and DKIM to decide what to do with emails that fail the checks of its two buddies. This is actually decided by the domain owners, who publish a policy on the subject. DMARC also generates reports that let the domain owner know who’s sending emails on his behalf. So, to use our example, the DMARC is like your party’s chief security officer: not only does it make sure that the guest list and wax seal are checked, but it also decides what to do with intruders. And, of course, keeps detailed records of who has tried to get in and what their status is, for even greater security control.

Want to ensure your deliverability on a technical level? Start with this:

  • Authenticate your emails with SPF, DKIM and DMARC.
  • Monitor email performance with email analysis tools.
  • Keep a clean suppression list to avoid sending emails to contacts who have unsubscribed or bounced.

Common email deliverability problems

If we’re going to explain what is email deliverability, we also need to talk about the problems we encounter when dealing with it. That’s why we’ve put together a non-exhaustive list of the most common problems, along with possible solutions to remedy them and keep your communications flowing smoothly.  

A high bounce rate

If the emails you send never reach your contacts’ inboxes, there’s no point. And that’s what the bounce rate is all about: it’s actually the percentage of emails you send that aren’t “delivered” and are returned to the sender.

This rate is essential for the deliverability of your emails, because it has a direct impact on your reputation. Email service providers (Gmail, Yahoo, Outlook…) monitor this bounce rate. And if your bounce rate is high, it means you’re sending emails to invalid or non-existent addresses, and your email list is probably poorly managed. As a result, these providers may classify you as undesirable, and your deliverability will take a big hit.

The best way to avoid this situation is to regularly update and clean up your email list. Check addresses when they are collected to make sure they are valid.

spam folder visual

The spam folder

The spam folder is actually managed by email service providers, who place unsolicited or potentially dangerous emails in it. And the big worry is that when an email arrives in the spam folder, it’s highly unlikely that the recipient will see or open it. But this has an impact on all communications. So for companies sending out important messages such as order confirmations, delivery notifications or password resets, for example, this can be very problematic. The quality of your communications and your reputation can suffer enormously and, as if in a vicious circle, you can be seen as less reliable and end up in the spam folder even more often.

Don’t want to end up in spam? Examine the content of your emails: eliminate spam “triggers”, improve the engagement rate of your contacts and authenticate your emails. This will be an excellent start for a better email deliverability.

A low open rate

The aim of email communications is to be read. The open rate is the percentage of emails sent that are actually opened by the recipients. But if your contacts don’t open your emails, it could mean they’re not relevant or interesting… This will impact your reputation and ultimately send you to the spam folder. This could lead to a decrease in engagement from contacts who will no longer see the communications and affect your business objectives.

To ensure your emails are opened, don’t hesitate to try out different styles or types of email subject. Personalization is also an element that encourages contacts to engage and open an email, for example. And finally, segment your list so you can send more relevant content that will interest your target audience.


Deliverability is an essential factor in the success of your transactional emails. By understanding the key elements and implementing best practices, you can significantly improve the deliverability of your emails and ensure that your messages reach their intended audience. Regular performance checks, email authentication and maintaining a quality email list are essential steps in this process. Looking for a solution you can rely on to send your emails? Get in touch with us! Naxai can help you optimize your email communications and achieve better results.

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