November 26, 2018 7 minutes to read

Preventing emails from being classified as spam. 7 Steps to improve Email Deliverability

The client approached us with the task to audit email marketing for several projects.

Email marketing generated a relatively small percentage of turnover, but the Client saw that people who opened emails were more likely to buy through other channels.

Before we started to cooperate, the Client used their own solutions for email deliverability — a system based on Amazon Simple Email Service (Amazon SES). We conducted an overall email marketing audit, which includes an email deliverability audit.

Here is a working checklist to improve email deliverability that we use.

1. Setting up regular deliverability monitoring using postmasters.

Regular monitoring should be set up with the help of Google Postmaster, Yandex Post Office и Postmaster. Then, it is worth analyzing reports on these postmasters.

Thanks to this, you can control message delivery to the listed mailboxes, collect user complaints about the mailing list, and control the platform from which the mailing is sent. Postmaster statistics example

We gave the following recommendations to the Client:

  • Set up Double Opt-in so that the user confirms the newsletter subscription. This helps to weed out spam bots, incorrect addresses and thus improves the statistics generally. There is more to read on Double Opt-in here: Soft and Hard Email Bounces.
  • Set up a welcome email series. It is necessary that after having subscribed the user receives welcome emails as soon as possible. In this way, they won’t forget that they have subscribed, which means that later they will not mark the email as spam.

2. Checking the email database for validity

The low percentage of email deliverability may be due to the fact that there are a lot of inactive or unconfirmed emails in the database. In any database, even the best one, there are some invalid email addresses, duplicates, addresses that no one visits anymore, or just overflowing mailboxes that appear over time. Therefore, you need to check the database for validity on a regular basis.

3. Analyzing deliverability dependency on IP addresses

In most cases, there are many senders on the same sending service IP. Within the same Amazon SES, one project may have a good reputation for IP addresses, but another one — not so much.

And this is more likely not because of what they send, but rather because of others who send emails from these IP addresses. Therefore, for large senders it is important to buy their dedicated IP addresses and warm them up — using them to send to the most loyal part of the base first of all, so that the mail systems could make sure that people read, click and do not unsubscribe. And only then deal with the whole database.

Be sure to pay attention to the reputation of IP addresses, because here is an example of a bad situation:

4. Implementing Feedback Loop

Feedback Loop (FBL) is a special format in which if a user clicks “this is spam”, you, as the sender, receive a notification about this so that you can unsubscribe this user and not send them anything again.

5. DMARC, SPF and DKIM Policy

DMARC (Domain-based Message Authentication, Reporting and Conformance), SPF (Sender Policy Framework), DKIM (Domain Keys Identified Mail) are the rules on what to do if emails are not sent from the sources that you specified as your servers and IPs.

The graph shows that part of emails in March stopped being checked by DMARC.

The Client had the “None” policy on, that is, no action to be taken. We recommend using the “Quarantine” or “Reject” policy so that malicious emails end up in spam or the server refuses them completely. Thus, some of the sender’s emails may end up in spam, but the company will quickly detect this and make changes to the settings, without having someone send something odd on the company’s behalf.

6. Setting up monitoring via EmailStream

EmailStream is a service that allows you to track whether your emails have ended up in the inboxed at, Gmail, Mail or Rambler, Yahoo!, Yandex.

Update as of 2021 — EmailStream has closed down. We are now testing alternatives and going to update the material.

You subscribe the emails generated by this service to your newsletter and see if they end up in the inbox or spam.

All the generated mailboxes need to be subscribed in the same way — so that each of the generated mailboxes gets into the mailing list and autoresponders segments identically. The scheme where 10 mailboxes are subscribed to one autoresponder and the other 10 — to the general mailing list does not work.

Then, once a week you need to look at the monitoring reports.

7. Testing all emails with MailTester

MailTester allows you to see if the message is classified as spam and shows what settings are registered for it: SPF, DKIM, DMARC, whether the sender is in the most popular blacklists, and what problems there are with the email layout.

This is a good tool, and it is worth sending all kinds of emails to it from all possible address options. And not just test / test by content, but real examples of emails that are sent from these addresses (with the layout, email subject and content).

  • For example, typical emails from Google Suite, MailChimp, Mandrill, invoiced to the user via Zoho Books or PayPal, and all other possible options that the user receives on behalf of your domain.
  • And from all the addresses: promo mailing service, trigger email service, emails from site / store managers, etc. The service will check if there are any errors in the SPF, DKIM, DMARC settings, what’s wrong with the layout and whether you get into spam, as well as whether there are problems for this particular sender.

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