Best practices, Deliverability

How to Monitor and Measure Email Deliverability?

Bartosz Gajewski, 12 April 2022


What Is Email Deliverability?

While talking to eCommerce store owners, marketing specialists, or reading various reports on email communication, you may often get the impression that the main criteria for measuring it is the number of opens, clicks, or completed orders.

Of course, the conversion rate is very important. It reflects the influence of prepared offer and performed campaign on the subscribers’ reaction, which later has a direct effect on sales results.

However, it’s not the only rate you should pay attention to when analyzing the effectiveness of your mailings. During this process, you should carefully review both the status and level of email deliverability.

This term in the eCommerce business refers to the actual number of delivered and rejected emails within e.g. a particular campaign. It’s then recommended to regularly monitor and maintain its high level.

In fact, deliverability is always in direct relation to conversion rate. The higher it is, the more likely to get better open and click rates. Having such increased subscriber activity builds a good reputation for your mailings among mailbox providers, which could later guarantee to achieve high email deliverability.

Deliverability is therefore an indicator that, along with open and click metrics has to be constantly tracked. With it, you can take care of a solid database hygiene strategy, control email address validation, check server IP reputation, or track the reaction of ISPs to performed email campaigns.

It can also provide a lot of valuable information that, while used properly, may help to build more effective email communication. However, how to monitor deliverability will be explained in the following article.

How to Monitor Email Deliverability?

Despite the major growth of the eCommerce industry and email communication itself, it’s still very common to hear that for many senders deliverability monitoring is based primarily on customers’ feedback.

Of course, this simple method of verification is correct and cannot be denied in any way. After all, customer feedback, complaints, and suggestions are the best source of developing a product or service.

The same applies to deliverability. Surely you are familiar with the situation when a dissatisfied customer called you to say he didn’t receive an invoice or an order confirmation. Only then do you begin to realize your emails may have lower deliverability.

Advanced Email Analytics

Another method of monitoring deliverability, which is usually used by Sales Departments, is analyzing the increase or decrease of order completion rates. In many cases, only a fall in online sales makes senders begin reviewing the possible reasons for such a problem very carefully. However, it often turns out that poor sales numbers are not necessarily caused by it.

Some other things such as prepared offers, wrongly selected groups of recipients, or too frequent campaigns may also have an impact on this situation. Moreover, based on sales results, you can control only the marketing email deliverability, at the same time ignoring transactional traffic. This being said, any method by which a sender begins to verify deliverability is good, though not always right.

The whole monitoring, however, cannot be based on customer complaints or sales figures. Instead, they should be a form of incentive to start working on analyzing and solving the issue.

While getting a deliverability support ticket, it’s good to have access to advanced analytics which makes it quick and easy to verify the situation. Nowadays, it’s a must-have for every sender who wants to operate professionally in the eCommerce market.

Benefits of Using Advanced Sending Systems

Fortunately, more and more mail systems offer their users the ability to generate specialized data on performed mailings. Before choosing such a tool, make sure to check what information it provides and how it is collected.

Remember the more detailed analytics – the easier it is to identify the cause of a potential problem. To give an example, EmailLabs not only informs its customers whether an email was delivered but also provides an analysis of received bounces. Relying on ISPs’ feedback and RFC documentation, EmailLabs categorizes all bounces to give its customers a full picture of their deliverability.


It is worth mentioning here that mailbox providers, due to security and email privacy policies, don’t share information about how messages are classified in the inbox. Plus, this is also affected by their anti-spam policy, in which rules are kept secret.

This means that no matter what system is used to send mailings, you may receive at least a confirmation of successful message delivery to incoming servers. Still, you won’t have any information to which tabs they were delivered. To specify this more precisely, you can use two additional tools.

Seeding List i Feedback Loops

The first one is a Seeding List. It’s a list of test email addresses to which messages are sent to check where they are delivered and how displayed in different mailboxes and email tools. Only this way a user can verify whether a message is potentially delivered to the main inbox or any other folders.

Such deliverability verification should be done periodically from time to time or before each larger, more significant mailing. Email classification is a dynamic process that depends on constantly changing anti-spam filters or users’ responses to received messages.

For this reason, we are strongly advising our customers to use the Seeding List during their campaigns as well. Changes in a redirection of email communication are done automatically by ISPs and could happen even in the middle of a running campaign. Thus, results provided by this method are for review only and cannot be considered as a mandatory evaluation for all sent messages.

The Seeding List service is also offered by EmailLabs. You can reach out to our Sales or Customer Service to discuss the terms and conditions of its implementation including monitoring and monthly report preparation with summarized results.

Another service, that provides more precise information about email deliverability is Feedback Loop. It has been introduced only by some foreign mailbox providers such as Yahoo or Microsoft. Recently Grupa Wirtualna Polska has joined the group.

Feedback Loop informs the Sender that the recipient has marked the message as unsolicited (clicked “This is Spam” on email). As a result, such complaints drive future emails to a subscriber’s spam folder. Feedback reports are taken very seriously by ISPs.

They may prove the sender is actually sending unsolicited messages or his contact list has a low hygiene level and is poorly managed. For this reason, even just a few such markings may cause all of the sender’s traffic to be directed to the Spam folder by any provider.

That’s why it’s always good to verify whether a mail system has a feedback loops mechanism implemented. By using it, you can closely monitor the deliverability rate and make sure it doesn’t drop.

How to measure deliverability?

The deliverability rate can be measured in a very easy way. It presents the percentage of the number of emails delivered divided by the number of emails sent. This will provide an indicator of what level of deliverability is maintained. But the analysis shouldn’t end here.

While calculating the deliverability, it’s important to check all the bounces, i.e. undelivered messages. We recommend reviewing them at least according to mailbox provider and received SMTP codes. Such a simple verification might show, for example, which receiving servers are blocking email traffic and why.

Based on this, many senders realize they have e.g. incorrectly configured servers or domains. Also, it’s worth paying close attention to hardbounces. In most cases, they indicate that in our contact database are invalid or permanently inactive email addresses, which cause unnecessary damage to email deliverability results and servers’ reputation. Therefore, they should be systematically removed from subscribers’ lists.

Before you start measuring your deliverability, however, it’s still a good idea to determine what exactly it should apply to. You can track it for a certain campaign, ISP, individual email address, or delivery time.

There are many options, although much depends on your technical capabilities. That’s why it’s so important to choose the right tool which will enable you to collect as much data as possible from performed mailings. Especially if you want to carry out multi-level deliverability analyses.


A sender who wants its email communication to be delivered effectively should systematically monitor the deliverability rate. Yet, it’s not an easy thing to do, because not all data is available via ISPs. Those, which can be provided, require appropriate processing and analysis.

Therefore, it is advisable to use third-party systems such as EmailLabs, which offer their customers advanced analytics of performed messages. As a result, you’ll be able to react quickly to deliverability issues and take care of other things related to your email traffic, helping you to systematically increase conversions from this communication channel.

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