Understanding the top factors affecting email deliverability

We talk a lot about Domain-based Message Authentication, Reporting, and Conformance (DMARC) and email authentication and how important it is for multiple reasons, including deliverability.

But what are the other things that can impact email deliverability? What are the rest of the variables in that deliverability equation?

Learn more about what factors are affecting your deliverability and what you can do to improve it.

Deliverability success: A mix of settings and signals

Defining deliverability success is easy. Success means your email messages are getting delivered to the inbox, not to the spam folder, and not rejected or blocked.

Understanding what goes into deliverability success—what affects email deliverability—can be a little more complicated, but here’s an easy starting point.

It’s all about settings and signals.

Settings: Email authentication, IPs and domains, and more

This is where email authentication protocols like Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and DMARC come in. Ensuring that the mail you send properly authenticates ensures it can be reliably traceable back to you as the sender.

Email authentication, like DMARC, helps deliverability for two really important reasons. First, by standing up and loudly proclaiming, “This email is my email!” you’re making it easier for inbox providers like Gmail and Yahoo to separate good mail from bad mail.

Second, you’re giving those inbox providers a reliable and stable identifier to attach reputation measurements. Your sending IP addresses and authenticated email domains are your calling card or Caller ID when it comes to being recognized for the email messages that you send.

“You know how credit card companies will block suspicious transactions and contact you to protect your available credit and credit score? Well, DMARC works similarly for a company’s sending reputation, as there is a sort of ‘credit score’ for gaining the inbox with marketing mail.”

Travis Hazlewood, Head of Email Deliverability at Ortto

There’s also a whole bunch of server-level or behind-the-scenes configurations necessary to send email properly. These include:

• Necessary headers
• Encoding messages properly
• Encrypting connections
• Controlling how fast a mail server attempts to send messages

These do matter for deliverability purposes, but most email senders don’t see these settings, as most email sending platforms, like email service providers (ESPs), handle these settings automatically and system-wide.

Signals: Positive and negative reputation feedback

Deliverability successes and failures are quite often reputation-driven. While getting the technical bits correct helps get you up to the front door to request access to the inbox, the next step is going to be whether or not the spam filtering lets you over that threshold to drop your email message into the desired folder.

Think of the spam filter as a bounce to an exclusive club. They’re sizing you up when you approach by reviewing the reputation data associated with your IP addresses and domains. Does that data identify you as a good sender or not?

Reputation data can take many forms. A negative reputation can include:

• A high percentage of spam reports
• A high bounce percentage (meaning that the list you’re sending to might have an excessive percentage of invalid addresses)
• Low rates of engagement or interactivity
• Being listed on a popularly used blocklist like Spamhaus or SURBL

On the other hand, a positive reputation generally includes feedback points that suggest that your mail is wanted and interesting to subscribers. It’s all about the interactions:

• Is your mail engaging?
• Is it expected?
• Is it receiving a relatively high number of opens and clicks?

All of these factors help boost your email reputation, along with your chances of getting delivered to the inbox.

Putting it all together to improve your deliverability

So, which of these things affects email deliverability? They all do.

A modern spam filtering system at an inbox provider is a complex piece of software and automation that reviews millions of data points on billions of messages. It takes all of these different bits of information into account and constantly revises its viewpoint and decisions about whether or not a given email message merits inbox delivery. Where you land when your score is computed will be based on all of these factors. 

Too many negative data points and/or technical failures could mean that your email messages are rejected outright. If it’s slightly better (but not good enough), you’re likely to see your email messages land in the spam folder. If you do everything right, and you’ll pass all of these tests, have a good reputation, and see those email messages reliably land in the inbox.

Leverage DMARC for improvement

DMARC is an important part of this deliverability equation. Updated email sender requirements at Google and Yahoo now require DMARC, and with bad actors hunting for imperfectly secured domains, security best practices to keep your email safe are more important than ever.

Valimail empowers you to comply with modern inbox provider requirements and allows you to move beyond the vulnerabilities of a p=none policy. Our solutions offer clarity, support, and the technological prowess needed to implement a reject or quarantine policy efficiently.

Ready to protect your domain and boost email deliverability?

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