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Email delivery and deliverability

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Hello newsletter fans,
How are you doing? Over here in the Netherlands 🇳🇱 it’s very noticeably fall. It’s raining a lot ☔, the days are getting shorter and lots of people have the sniffles 🤧
On the plus side, that means more time to read. So I went through SendGrid’s “2019 Email Deliverability Guide”, which arrived in my inbox last week. It’s not the most entertaining reading, but important stuff, so I thought I would summarize the most important parts in today’s issue of The week in newsletters. Our CTO Mo, who knows everything about deliverability, helped with some of the thornier issues.
Hope you find it helpful. If you do, please forward this email to a colleague or peer. Thank you 💌

Email delivery and deliverability
To get started, I liked Mailjet’s explanation of the difference between email delivery and deliverability:
Email delivery is whether or not your audience’s ISP (e.g. Gmail) received your emails. Deliverability is on emails that hit the inbox.
Delivery is easy. All it takes is an email address to get your message to the recipient’s email provider. The hard part is to get providers like Gmail, Microsoft or Yahoo/Oath/Verizon to show that message to the user in their inbox. That’s deliverability.
There are three main elements that determine deliverability:
  1. Infrastructure and authentication
  2. List quality and sender reputation
  3. Email content
Infrastructure and authentication
Infrastructure and authentication is the technical aspect of deliverability. It’s a number of configuration settings that allow the email providers to check if the message was sent by the person who identified themselves as the sender. It might sound a little crazy, but it’s actually almost as easy to spoof an email sender address as it is to write a wrong sender on a snail mail envelope.
Email spoofing can be easily achieved with a working SMTP server and mailing software like Outlook or Gmail. Once an email message is composed, the scammer can forge fields found within the message header such as the FROM, REPLY-TO and RETURN-PATH addresses. After the email is sent, it will appear in the recipient’s mailbox that appears to come from the address that was entered.
Email providers have created three safeguards that allow them to check if the email message was sent from the same domain as the sender’s email address to prevent spoofing.
ReturnPath has a good glossary of these settings:
SPF Record: SPF, which stands for Sender Policy Framework, describes a list of IP addresses that are allowed to send emails from a specific domain.
DKIM: DKIM stands for Domain Keys Identified Mail and is the next stage of Domain Keys. DKIM uses a pair of cryptographic keys, one private key that all outgoing messages are signed with and one public key that is published in DNS.
DMARC: DMARC, or Domain-based Message Authentication, Reporting & Conformance, standardizes how mailbox providers authenticate and deliver mail by utilizing existing SPF and DKIM records. Senders can indicate if their emails are protected by SPF and/or DKIM, and tell receivers to junk or reject a message if neither of those authentication methods passes.
There’s a nice tool that let’s you check whether everything is configured correctly: When you go to their site, mailtester will give you an email address. If you send a preview of your newsletter to that address, mailtester will check your configuration settings and give you a report with a score:
List quality and sender reputation
The second element of deliverability is list quality and sender reputation, which are about your readers and how they react to your email messages. It’s very similar to what newsletter publishers consider engagement. The SendGrid deliverability guide has a good list:
How many times messages are forwarded, ignored, deleted without being read, moved from one folder to another and how often a sender is added to a contact book
So if you feel so inclined to help me improve my deliverability, it would be super duper awesome if you could reply to today’s issue with a simple “Thanks, Mark.”. It would not only make me very happy to hear from you, but also send “message read” signals to your provider and add my email address to your address book, which would greatly improve my deliverability 💌
The key to improving sender reputation is to avoid having non-engaged email addresses on your list, because they can negatively affect deliverability. That’s important because it could lead to newsletters not being delivered to readers that do want to read it. Some useful tips are for sender reputation are:
  • Do not import old email addresses but start to build your list slowly over time
  • Remove all bounces and invalid email addresses
  • Clean up unengaged addresses from time to time
  • Warm up a new list, i.e. start with a sublist and add new subscribers over time
  • Use double opt-in for new subscribers
  • Send consistently, at the same time every day or the same day every week
Here’s a quick look at the engagement of readers of The week in newsletters. The table shows which percentage of issues readers have opened. The majority has opened each and every issue (thank you, you are the best 🙏), and most other at least a majority. But there are also a few who have opened very few (don’t worry, I won’t name names 😉)
A bit of a scarier scenario is spam bots, that can hit your list and bring engagement down or even expose you to so-called spam traps, a fake email address that should never receive any email and signals spam to providers. Dan Oshinsky wrote about his experience with spam bots at BuzzFeed in the April edition of Not a Newsletter:
We were the victims of a spambot, which had been crawling the web looking for an email subscription form like ours. It had found the main BuzzFeed subscription page. We didn’t have any sort of authentication tool on that page to confirm that the email addresses being signed up were real, and we weren’t using a double opt-in process to add an extra layer of verification. Thousands of email addresses were being added to our lists, and those spammy emails could have caused huge damage to our email program.
ReturnPath have a nice service that helps you check your reputation: Here’s what that looks like for, the sending domain of Revue’s newsletter platform.
Being a newsletter service obviously means that Revue sends a lot of email, hence the volume is high. The sender score is, however, high at 97 out of 100, meaning that SenderScore considers Revue a trustworthy sender from a technical perspective.
Email content
The third and last element is the email content. This is not just the words, but also the template, links, images, or subject line.
Concerning the words, Mailjet has a funny overview of words to avoid. Were you using any of these?!?
While those spam words are pretty obvious, using a link shortener might be more surprising. They do make URLs look neater, after all. But they are spam signals, too, as SendGrid explains:
Link shorteners are often used by spammers to mask malicious links that lead to ransomware and other infected pages. As a result, inbox providers might flag them in your messages. 
The bottom line is, that all three need to be in order for your email to be delivered to the inbox. You need to be properly authenticated, have a good sender reputation and trustworthy content.
The week in newsletters
You made it through the deliverability section. Well done 👏 Now on to what else is worth reading in newsletters this week 📬
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