If you’re looking for more conversions, revenue, and customer engagement then it all starts with your email deliverability.
For the last fifteen years of my professional career, and as the Senior Director of Deliverability at Maropost, I’ve specialized and concerned myself with one thing: email deliverability.
While email deliverability has changed a lot in fifteen years, it’ll always remain relevant and of primary significance for email marketing.
Which is why I created a deliverability checklist to guarantee the success of our deliverability… and I’m sharing it with you today.
This 8-step checklist is the first thing we look at with all new accounts when onboarding them with Maropost.
It compiles the most fundamental and most essential steps for email deliverability success and provides invaluable insight on the health of the client, their campaigns, and their data.
On average, after running through these eight steps, accounts see an immediate 15–20% increase in inbox placement and a long-term increase of up to 50% for all engagement and conversion metrics.
Use this as the ultimate tool to ensure that your deliverability is on the right track.
Here’s an excerpt of the checklist…
You can download the complete checklist here.
But before we can dive into the details of each step and really understand how to optimize them, first we need to understand exactly what email deliverability is and how it’s determined…
What is Email Deliverability?
Deliverability is the FIRST step in the email process.
Before opens and clicks, before landing pages and conversions, before drip campaigns and upsells, you must be sure your customers are even receiving your marketing campaigns. And that’s deliverability in a nutshell: getting your emails to your customer’s inboxes.
Because there are a lot of barriers.
Internet service providers (ISPs), inbox providers, email service providers (ESPs), and third-party companies all want to protect recipients from spam. In fact, 1 in 5 of all commercial emails don’t land in the inbox.
Contrary to common opinion, deliverability is not measured by the “delivered rate.” The delivered rate simply measures the number of emails that don’t receive a hard or soft bounce.
Deliverability is all about landing in the inbox.
So, if you had a high delivered rate and a high spam rate, then your inbox placement and deliverability is actually very poor.
Poor deliverability means you’re not reaching your customer’s inboxes. The fewer delivered emails in the inbox, the fewer key performance indicators (KPIs) across the board, and that’s going to negatively affect your bottom line.
The more delivered emails to the inbox? The more engagements, conversions, and revenue. That’s the Maropost deliverability funnel to revenue…
What Affects Deliverability?
Broadly speaking, deliverability can be measured in two ways and from two perspectives.
1. From the Recipient’s Perspective
Inbox providers pay attention to how recipients interact with your emails and whether that interaction is positive or negative.
Positive actions, such as opening an email or adding the sender to the address book, indicates that the email is relevant and will improve your deliverability.
Positive actions include:
- Email read
- Email clicked
- Email replied to
- Email moved to other folder (not “spam” folder)
- Sender or domain added to address book
- Email forwarded
- Email marked as “not spam”
- Email scrolled through
Negative actions, such as marking the email as spam, will adversely affect your deliverability. They include:
- Message marked as “spam”
- Email not read
- Email not clicked
- Email deleted
You should already be aiming for the positive actions in pursuit of your KPIs – and now you know they’re doubly important because they affect deliverability, too!
The good email marketer knows how to think like their audience.
So, always be asking yourself: How can I get my recipients to engage positively with my emails?
2. From the Sender’s Perspective
As the sender of the email, it’s up to you to ensure that you have the best deliverability practices executed and running.
There are three areas that you need to concern yourself with:
This is the foundation for your emails and deliverability strategy, and it’s key that it’s set up correctly.
To do this, ask yourself the following questions:
- Have you set up the correct foundation for your emails and strategy?
- Are you using the right type of IP and authentication?
- Have you set up your feedback loops correctly?
These are the recurring activities that you need to maintain.
You should already be following email acquisition and list cleansing best practices; we’ll explore how these specifically affect deliverability further in this post.
Are your email marketing processes designed with deliverability in mind? You can ensure they are by answering these three questions:
- Does your email acquisition follow deliverability best practices?
- Does your list cleansing follow deliverability best practices?
- Are you taking the correct steps to avoid spam traps?
This is the actual email that gets sent to recipients.
There’s the structure of the email, which you’ll need to set up once per template, and there’s the content of the email, which you’ll need to set up per every email blast:
- Have your email settings and format been optimized?
- Is your email content deliverability-friendly?
Infrastructure, processes, and email will be the main focus of the checklist.
We’ll go over all three areas in more detail and tell you exactly what steps you need to take to master each one, so you can be sure you’re your deliverability and inbox placement is the best it can be.
Ready? Let’s get started!
Infrastructure is the foundation of your email and deliverability strategy. This is what you need to set up (or ensure that it’s been set up correctly).
Step 1: Choosing the Right Type of Internet Protocol
An IP, or internet protocol, address is a unique string of numbers that identifies your computer or network.
IP addresses have an associated deliverability reputation metric that inbox providers look at.
There are two types of IP addresses:
A dedicated IP address is used by a single sender or company.
No other marketers can use it.
The reputation is wholly determined by the emails of that single sender or company.
A shared IP address is used by multiple senders or companies.
The overall reputation for a shared IP is based on all the senders – so the reputation cannot be managed by an individual sender or company.
So, which type of IP is right for you? Generally speaking, email marketers should use a dedicated IP to exercise maximum control.
However, shared IPs are acceptable under two scenarios:
- You send under 50,000 emails a month
- You send emails and campaigns infrequently (more than a month between each interval)
In these two scenarios, a shared IP is preferable as it’ll give you a more consistent email send and volume, which matters a lot.
On the other hand, if you are a high-volume sender, one dedicated IP might not be enough.
Consider segmenting critical emails to a different IP from standard or promotional emails.
This will ensure your critical emails have the highest deliverability rate and will not be diluted by other streams with poorer deliverability scores.
Step 2: Setting Up the Right Types of Authentication
Authentication allows the inbox provider, third parties, and the recipient to verify the identity of the sender, and it is normally set up by your ESP.
Authentication creates a portable and specific reputation specific to your brand.
If you run your own mail server, you will need to edit your Domain Name System (DNS) records and mail server settings to comply.
Here are the four types of authentication you need to confirm have been set up:
SPF (Sender Policy Framework)
SPF verifies the sender address.
It cross-checks the domain in the “Mail From” line of an email against the published record that the sender has registered in the DNS.
DKIM (DomainKeys Identified Mail)
DKIM authenticates that an email was sent from a legitimate and authorized source.
It requires the sender’s computer to generate public/private key pairs and then publish the public keys to their DNS records.
TLS (Transport Layer Security)
TLS encrypts and delivers mail securely, ensuring that no-one else is intercepting or tampering with your emails.
TLS is the email equivalent of HTTPS.
DMARC (Domain-based Message Authentication, Reporting, and Conformance)
DMARC is a standardized method of authenticating via SPF and DKIM. DMARC is optional but it will ensure that your authentication results are consistent across ISPs and inbox providers.
Step 3: Setting Up the Feedback Loops
Having one of your emails marked as spam is obviously a negative action and will have a tremendous adverse effect on your deliverability.
However, senders and ESPs aren’t able to see or measure an “email marked as spam” rate.
To overcome this limitation, most inbox providers offer a service called feedback loop processing.
Feedback loop processing means the inbox provider will email the sender directly when a recipient has marked one of their emails as spam.
This tells you which recipients have marked your emails as spam, when they did it, and to what email.
It’s absolutely crucial that you set up feedback loops!
You need to know when a recipient thinks your email is spam, so you can take the necessary steps thereafter. Whether that’s:
- Removing the recipient from your mailing list
- Segmenting them better
- Or simply improving your emails
You’ll need to set up feedback loops separately for each inbox provider.
Take a look at your mailing list and see which inbox providers you send to the most and set those up first.
We’ve included links to resources that will help you begin the feedback loop process with the four biggest inbox providers:
Processes are the recurring activities that you need to maintain.
Of those processes, we’ll focus on email acquisition and list cleansing – both of which are staples in email marketing.
We’ll continue with Step 4 and explain what spam traps are, so you can avoid them.
Step 4: Avoiding Spam Traps
Spam traps are email addresses that are specifically used to identify poor email acquisition or list cleansing. There are two types of spam traps:
Recycled Spam Trap
Recycled spam traps are email addresses that once belonged to a real person.
However, these email addresses have since been abandoned and appropriated by spam trap operators.
If you send emails to a recycled spam trap, that indicates that you have poor list cleansing and data sanitation practices, and this will NEGATIVELY affect your deliverability.
(Don’t worry though – we go over best practices for list cleansing in Step 6, so keep reading!)
Pristine Spam Trap (AKA a Honeypot)
Pristine spam traps are email addresses that have been created for the specific purpose of catching spammers and senders with poor email acquisition practices.
Spam trap operators will often hide their spam trap email addresses on websites, so they are only visible to email harvesting spiders. When spammers harvest email addresses from websites, they will also gather the honeypots.
Sending emails to pristine spam traps indicates that you have poor email acquisition practices, and this will negatively affect your deliverability.
Step 5: Optimizing Email Acquisition
Deliverability shares the same golden principle as email marketing when it comes to email acquisition: You want relevant and interested recipients who will actually open and engage with the emails you send.
These next points will guarantee that you’re only collecting the most relevant emails and that you’re processing them in the optimal way for deliverability.
Avoid Third-Party and Poorly-Sourced Lists
Quality, not quantity, is what matters to deliverability.
You want recipients who are interested in receiving and engaging with your emails.
Third-party lists such as appends, rentals, and purchased lists have low opens, clicks, and engagements – all negative actions which have an adverse effect on deliverability.
Third-party lists are also much more likely to have spam traps, which can result in your IP being completely blacklisted by inbox providers.
Run Basic Validation
If your landing pages don’t have basic validation, you’ll need to validate your email lists after the fact.
To do this, remove role accounts (e.g. firstname.lastname@example.org), fake addresses (e.g. email@example.com), and errors (e.g. firstname.lastname@example.org).
Consider Double Opt-In
Also known as closed-loop confirmation, double opt-in is the gold standard to get emails and confirm relevant interest.
Double opt-in requires recipients to confirm their subscription after providing their email addresses.
This will guarantee that they are real people who are interested in receiving your emails.
Double opt-in confirmation is also a great time to get additional information and the contact preferences of the recipient.
If you’re sticking with single opt-in, be sure to secure your landing page with CAPTCHA. This will prevent robots from registering with illegitimate addresses.
Quarantine New Recipients
Quarantine new recipients until you can send them a welcome message and you can confirm that there is not a hard bounce.
This prevents you from adding bad email addresses to your list.
Limit Your Welcome Email Volume
If you find yourself with a backlog or a high-volume of new recipients, you’ll want to ration out your welcome emails.
Inbox providers are always wary of huge email blasts to new addresses as this is indicative of spam. You also risk a higher chance of negative actions when sending to new emails for the first time.
Instead, you should limit and mix your welcome email volume with your regular email blasts.
A good rule of thumb is 10% welcome emails and 90% regular emails. This way, regardless of the welcome emails’ engagement, the overall positive recipient actions will still be high and your deliverability won’t be penalized.
Set Expectations with Your Welcome Email
It’s important to clearly set expectations with your welcome email. This will tell your subscribers what to expect and set the tone for future engagement.
Step 6: Optimizing list cleansing
It’s not enough simply to optimize your email acquisition.
You need to ensure that email addresses in your email lists remain active and relevant – or else you need to remove them.
Remove Inactive Subscribers
Inactive subscribers are either recipients who have lost interest in your email campaigns or are spam traps who were never interested in the first place.
Either way, inactive subscribers means your emails won’t be opened or clicked (or worse still, they’ll mark your email as spam!) – all of which are negative actions that will adversely affect your deliverability.
You should already be using campaign performance data to analyze email engagement, but it’s important to drill down to the individual recipients for list cleansing.
The general context and frequency of your campaigns and blasts matter when deciding how to define “inactive.”
If you’re sending weekly emails to a recipient, and they haven’t engaged in two months, then it’s clearly time to take a look at your journeys and funnels to see how you can get them to re-engage again.
(Find out how to Win Back Inactive Subscribers with a Reactivation Email Campaign.)
A good rule of thumb we follow is six months – that’s the maximum amount of time a recipient can stay without engaging.
Otherwise, it’s been too long and it’s best to remove them; they’re clearly not interested.
Worse, they could be honeypots that are hurting your deliverability every time you hit send.
Find and Remove Sources of Inactive Emails
It’s a good idea to routinely audit the sources of inactive emails.
Export any inactive emails and do a count based off the domain.
Are there any behavioral relationships to the source?
If so, you might want to add a validation rule excluding these email sources from your landing page or list acquisition.
Finally, there’s the actual email that gets sent to recipients.
Inbox providers and filters look at each individual email that is sent.
Keep the positive and negative actions in mind!
Remember, an email that drives position actions (such as opens, clicks, and forwards) will improve deliverability while an email with negative actions (such as being marked as spam) will hurt deliverability.
Step 7: Email Structure
You have to optimize the actual structure of the email. You’ll need to set this up every time you create a new template.
You do this by:
Including a Link to Unsubscribe
It should be EASY for recipients to unsubscribe.
There’s no point retaining recipients who have no interest in your emails – they’ll only drag your deliverability down.
Including a Link to the Preference Center
A preference center allows recipients to select the frequency and topics that best suits them.
Having a preference center allows you to tailor to the individual subscriber and this will boost engagement and deliverability.
Bonus Tip: Inserting the recipient’s preferences into the header or the footer of the email is a great way to let them know you value their subscription.
Confirming Your HTML
Most email editors will flag any HTML errors – but they’re not always perfect. Especially if you’re building an email template, you should always review your code and ensure it is correct and bug-free.
And this isn’t isolated to the back-end code.
Test, test, and test to make sure your email is rendering correctly on the front-end across all platforms!
Most ESPs have a display functionality that will show you it renders across different clients and devices.
If you don’t have that luxury, it’s a good idea to see what the most popular inbox providers your subscribers are using, set up test accounts for those inboxes, and send to those accounts to test manually.
Including a Plaintext and Web version of the email along with the HTML
HTML is the standard when it comes to emails.
But not all recipients and platforms enable HTML. It’s important to have a plaintext and web version of the email, too.
Having a plaintext version of your email is looked upon favorably by inbox providers while the web version allows you to provide a functional, offsite version of the email.
Step 8: Email Content
The truth is, email content doesn’t matter too much anymore when it comes to deliverability.
When email was just starting out in the 90s, content was the primary factor when it came to deliverability.
Today, reputation far outweighs content—but it’s still a good idea to follow my rules below and optimize your email content.
These rules also impact the general readability of emails, so they will improve your deliverability via position actions (such as clicks), too.
Balance Text and Imagery
Good design is universal.
That means a balance of text and imagery.
Whatever you do, don’t create email messages with a single image – this will almost certainly get you flagged as spam.
Instead, you should use a good balance between text and images.
The focus should be on communication and readability (i.e. text) with a complementary design (i.e. images).
Keep in mind that images don’t always render.
Certain recipients and platforms will turn images off. That’s why it’s important to have alt text (alternative text) for your images and to ensure that your email still makes sense if the images are missing.
Check Your Links
Email filters will analyze all the links in your email to see if they are reputable. Every link has a domain which has an associated domain deliverability reputation.
If you’re linking to third-party sites, you should ensure they’re legitimate websites.
In a similar vein, you shouldn’t advertise your website pages through spammers. If your website is found in “spammy” emails, it can affect your deliverability.
If you don’t know what base64 is, you’re probably not using it.
If you are using it – STOP.
Spammers use base64 to hide email content from filters.
Emails with a base64 encoded body or subject line are much more likely to be flagged as spam.
And those are the eight steps we go through to increase inbox placement by 15-20%.
Every aspect of email marketing influences, and is in turn influenced, by deliverability.
It’s important to adopt the deliverability mindset and truly integrate it into your email and marketing strategy, which the checklist will help you do.