Whether it’s financial, fitness, business or nutrition, all of us seek to establish routines robust with goals, checklists and reminders to motivate us daily to keep us on track and focused on the task at hand.

I’ve created this post specifically for email marketers as an EMAIL DELIVERABILITY CHECKLIST that every online marketer should routinely review as a reminder of the foundational stepping stones to solid email deliverability.

Before we can understand and can tackle email deliverability, we need to first understand and ask ourselves – “WHO OWNS THE INBOX?”

Is it Senders, Subscribers or Inbox Providers who own the inbox?

Litmus did a survey recently and asked its community what they thought. Here are the results:

I personally think it’s the subscriber who owns the inbox and the minute you forget that is when all your email deliverability nightmares will reign true!

Now that we got that out the way, let me present the crucial pillars of email deliverability.


I’m going to assume that you have the technicals covered:


You need to make sure that your email list is clean. What do I mean by “clean”?

A clean list consists of 2 parts.

First, you need to make sure that there are no invalid, “role” (info@, support@, etc.) or suspicious email addresses on your list (or added to your list).

Invalid email addresses are ones that no longer exist and will bounce back when sent to them. A high bounce rate can indicate a bad list and may cause deliverability issues if overlooked.

There are many list hygiene companies out there that can help you clean up your list.

Quick Tip:

A double opt-in signup process will tackle most of these types of bad addresses and prevent them from ending up on your list.

However, if you do NOT have a double opt-in list collection process in place, you’ll need to routinely monitor your new signups to ensure that such problematic email addresses do NOT get added (and most importantly continue to linger) on your email list.

Second, you need to ensure that “inactive” email addresses are either re-engaged or purged.

Inactive email addresses are “unresponsive” subscribers that have not opened or clicked on an email for a very long time. It is best to either re-engage these subscribers with special incentives and offers or to remove them altogether from your list.

Quick Tip:

Since the risk factors for having “inactive” contacts on your list are not fully validated, I always prefer to keep them on the email list and segment these subscribers, emailing them less frequently.


Much like your credit score, your sender reputation consists of metrics (that can go up or down) monitored by ISP’s and inbox providers to assess the risk level for your email campaigns.

A poor history and sending reputation will result in emails ending up in the spam folder or even worse – totally blocked!

You should routinely monitor your sending reputation and major blacklists to ensure that there are no major problems with your sending reputation.

Quick Tip:

You can user Sender Score from Return Path for a quick overview of your sending IP reputation.


So, let’s assume you’ve got all the points mentioned above covered and all your data is super clean (with proper bounce management), your list collection methods are following best practices and you’re on top of your sending reputation (IP’s and domains).

Now comes the “Engagement” part!

To fully optimize your email deliverability, you’ll need to direct your focus on overall metrics (open & click rates and low spam complaints) and Audience Management.

Although the normal email metrics (i.e. opens, clicks, etc.) provided by your email service provider play a role, ISP’s look at engagement a bit differently by also monitoring a subscriber’s inbox actions in deciding whether your email ends up in the inbox or not.

Here are the inbox engagement metrics ISP’s may consider:

Positive Engagement Metrics:
  • Reply Back – when your subscriber replies back to a message they received from you, it is one of the highest levels of engagement.
  • Not Spam – when your subscribers marks an email as “Not Spam”, it tells the ISP that the message should not be considered spam.
  • Archive or Move to Folder – when your subscribers move messages around and store them, it signals to the ISP that they care about your emails.
Negative Engagement Metrics:
  • Mark as Spam – when your subscribers mark an email as “Spam” or “Junk”, it signals to the ISP that the email was unwanted.
  • Delete Without Open – when your subscribers glance and delete (without opening), it may signal that they didn’t like it or are not interested in your email. (this is negative if it keeps happening over and over…)

How do you get more of the “positive” actions in the inbox you ask? Here’s a quick list of items:

  1. Killer Content – Send valuable content (that’s reliable and reputable) to build trust.
  2. Targeted & Relevant – With advanced marketing tools, you can target emails based on your subscribers behavior and interests to deliver a more personal and relevant email.
  3. Segment Your List – Further optimize by segmenting your list by interest to increase engagement.
  4. Sending Frequency – Stick to a consistent schedule. By over-sending, you’ll cause list fatigue & high churn or unsubscribe rates. By under-sending, your subscribers will forget about you and who you are.
  5. Listen – By listening to your subscribers or customers you gain their loyalty and they won’t be able to wait until your next email!
  6. Evaluate Metrics & Response Rates – How everything is looking from open rates, click rates, unsubscribe rates, conversions and more…

Next, it’s about audience management.

Your email subscribers have 3 main paths they can take in terms of engagement.

At the minimum, you need to monitor movement between these 3 paths (or segments):

1. Active Engagement:

This is the ideal path where the subscriber actively opens, reads, and interacts with your emails.

They might click on links, respond to surveys, or even make purchases based on your email content.

To encourage this path, it’s important to send relevant, personalized, and valuable content to keep them interested and engaged.

2. Passive Engagement:

In this path, the subscriber opens and reads your emails but does not actively engage with them.

They don’t click on links or respond to calls to action but they do show a level of interest by regularly opening the emails.

To move them towards more active engagement, you could try varying your content, using more compelling calls to action, or segmenting these subscribers for more targeted campaigns.

3. Disengagement:

Unfortunately, some subscribers will eventually disengage.

They stop opening emails, and might even mark them as spam or unsubscribe.

This could be due to a variety of reasons such as email overload, irrelevant content, or a change in their intent or interests.

To minimize disengagement, it’s important to regularly clean your email list, segment your audience for more relevant content, and not overwhelm subscribers with too many emails.

Also, consider sending re-engagement campaigns to try to recapture their interest.

In all paths, monitoring key metrics like open, click-through, and unsubscribe rates is crucial for understanding subscriber behavior and adjusting your strategy accordingly.

Overall “engagement” can only be measured over time and that is why it is vital to routinely go through your entire email program (from top to bottom) to ensure that all checks and balances are properly in place…

… AND… always remind yourself that being proactive and maintaining a good sender reputation is much better than trying to repair a damaged reputation after the fact.