Email Marketing

Mastering Email Deliverability in 2022

Getting an email into a recipient’s inbox is the first step in a successful campaign. The best offer, creative, and subject line won’t matter if the subscriber never receives the message.

In this post, I’ll address how to prevent email providers such as Gmail, Yahoo, Outlook, and others from blocking delivery or routing to spam or bulk folders.


Email marketing platforms — Mailchimp, Sendinblue, many more — report the percentage of “delivered” emails. But that includes messages in spam and bulk folders. Thus a 99% deliverability rate may sound good, but it doesn’t mean recipients saw the email. I’m unaware of a tool that calculates how many emails went to inboxes.

Email platforms count only hard bounces — those sent to nonexistent addresses — as undeliverable. Most platforms automatically remove those addresses.

Soft bounces are typically temporary blocks, such as full or unavailable inboxes or sudden volume increases to that address. Most email platforms resend soft bounces multiple times. But they usually count soft bounces as deliverable, resulting in a misleading rate.

Soft bounces once occurred only when an inbox was “full.” However, that is no longer the case as most providers offer larger inboxes for users and rarely hit storage limits.

Deliverability Problems

Here are three indicators of deliverability problems.

  • Decreases in opens and clicks. A breakdown of subscribers’ domains — i.e.,, — can narrow the problem. For example, open rates for Yahoo addresses suddenly dropping from 12% to 4% could indicate a block or a filter to spam folders.
  • Increases in unsubscribes. An increase in unsubscribes is not likely a deliverability problem. But it can infer user engagement, which impacts inbox receipt. An increase in unsubscribes could mean weaknesses in messaging, frequency, or overall sending strategy.
  • Degradation of Sender Score. Monitoring your IP and domain reputation weekly is vital to maintaining the health of your email program. Sender Score, a free service by Validity, formerly Return Path, is my go-to tool. It assigns a grade of 0-100, with 100 being the best.
Home page of Sender Score

Sender Score is a free service to gauge the health of your company’s email reputation.

Impacts on Deliverability

Senders. The history and practices of a sender affect deliverability. Senders with consistent, responsible email volume and frequency over time typically have high Sender Scores.

Recipients are the essential factor in deliverability. Email providers look at the overall engagement of subscribers as a key indicator of deliverability. If subscribers continually delete an email without opening or clicking, the provider will likely automatically filter emails into a spam bucket. This could lead to a total block. Thus senders should periodically remove unresponsive subscribers.

Email providers seek to reduce spam and unwanted messages for users while delivering legitimate senders to the inbox. This can be tricky. Providers frequently change algorithms to stay ahead of spammers. Unfortunately, the changes often snare legitimate senders.

Third-party blacklists such as Spamhaus and MX Toolbox maintain tallies of spam domains and IP addresses. Email providers include these lists in their algorithms. Occasionally responsible senders are mistakenly added to blacklists. Thus it’s a good idea to ensure your domain or IP is not included. If it is, a short email to the blacklist service will usually resolve the issue.

Apple Mail Privacy

Apple’s Mail Privacy Protection allows iOS 15 and macOS 12 Monterey users not to disclose whether they opened an email. Apple now shows all emails to those users as having been opened. The result is inflated open rates. Email providers are adjusting their algorithms accordingly.

MPP’s impact on marketers has been mixed. It affects only iOS 15 and macOS 12 users who open emails on the Apple Mail app and enable privacy protection. Android has not (yet) deployed a similar feature.

Early data from Sendgrid, the email delivery platform, suggests less than 5% of Google (Gmail) and Microsoft (Outlook) opens use MPP versus roughly 23% of Apple Mail opens.

Regardless, marketers will increasingly assess click rates, not opens, as the key email engagement metric. Tactics to encourage clicks, such as short content and compelling calls-to-action, will become common.

Key Pointers

In short, to improve deliverability:

  • Avoid significant changes in volume or frequency.
  • Monitor open, clicks, and unsubscribe rates.
  • Check your Sender Score and major blacklists.
  • Keep your list healthy by removing unresponsive subscribers.
  • Implement strategies to improve clicks.
Carolyn Nye
Carolyn Nye
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