Deliverability 101


Deliverability can be simply defined as “the ability to deliver email to the intended recipient’s inbox.” It is an important factor of a successful marketing campaign, which is why Extu prioritizes implementing various strategies to ensure that audiences are getting partners’ messages. We created a quick guide on the basics of Deliverability so that partners can see a high level overview of what deliverability is, why it’s important, and how it provides valuable insight for future campaigns. 

In 2020, 47% of email was marked as spam

How to Calculate Delivery and Deliverability Rates

Delivery Rate = Emails accepted at gateway ➗ Emails sent

Deliverability Rate = Emails delivered to inboxes ➗ Emails sent

Why is deliverability important?

You could have a perfectly curated email campaign with the right message and compelling content; but if they don’t reach your recipients’ inboxes, you’ve wasted your time and efforts. 
Deliverability rates are important because they ensure that your email marketing campaigns are efficient and as successful as possible. 
If your email makes it into your intended recipient’s inbox, you’ve already beat out hundreds of other competitors. Inbox providers filter and send billions of emails everyday straight to spam or junk folders. 
Understanding deliverability rates will quickly help you know what type of content works for your audiences and what doesn’t. 
If your emails are constantly getting marked as spam, your sender reputation score suffers. Your sending domain and ISP address have an online reputation! If your score is low, inbox providers may mark your future campaigns as spam.

How can I improve and maintain my deliverability rate?

Email Authentication
Configure DKIM, SPF, and DMARC records for your sending domain. It’s easy! Your Extu marketing consultant can help you set this up.

Setting Up a Subdomain
Pick a subdomain and allow us at Extu to set it up for you. A subdomain is important because it protects your parent domain’s reputation so that non-marketing emails (billing, for example) don’t risk getting marked as spam.

List Hygiene
Good list hygiene practices consist of a few different things such as creating a friendly sender name, using a recognizable sender email, using organic lists (not purchased), sending only to those who have opted in to your emails, and ensuring emails are up to date. 

Know best send practices like setting up proper content expectations for your audience, sticking to a consistent schedule, avoiding “spammy” subject lines (all caps, !!!, or win $), monitoring spam/complaint rates, and segmenting your email lists.

Friendly Sender Names
When you send someone an email, the name your account is registered under will show up in the From field on your message in the recipient’s inbox. Make sure to add your full name on the account and avoid one word names, phrases like SALES DEPARTMENT, or other unclear identification labels. This helps your messages avoid getting marked as spam.

List Size Checklist

Use this chart to find the recommended actions by list size (as described on the left) when sending emails:

List Size Sender Name Sender Email 2-Step Unsubscribe DKIM SPF DMARC Segment list
1-50 Required Required Recommended Required Required Required -
51-500 Required Required Recommended Required Required Required -
501-5000 Required Required Recommended Required Required Required -
5001-10000 Required Required Recommended Required Required Required -
10000+ Required Required Recommended Required Required Required Recommended


Authentication: a process that verifies a user’s identity

before allowing access to an email recipient’s inbox

Bounce Rate: the number of messages that are

returned as undeliverable by the number of emails sent

DKIM: verifies that an email’s content hasn’t

been tampered with before it reaches the recipient

DMARC: a policy that enables a brand to monitor

the all the key sending information for their

domain and then dictate what to do if a sender

appears suspicious

DNS record: a system that is used and supports

the authorization of domain for a particular service

Segmentation: dividing audiences into different

categories in order to create a customized campaign reach

Sender Reputation Score: reflects the behavior

and trustworthiness of a sender

Spam: also known as junk mail; unwanted digital information

SPF: authorizes specific outbound mail server IPs (ie ESPs)

to send on a domain’s behalf

Subdomain: a prefix in front of a primary domain

(such as a single letter or, for example, “email” in