The Ultimate Guide to Email Deliverability

For anyone with a newsletter, understanding email deliverability is crucial.

To start, let’s define it:

Email deliverability is when an email successfully arrives in a recipient's inbox.

And while we’re at it, let’s define a few other key terms with examples:

Email Service Providers (ESPs) send emails on your behalf (e.g., beehiiv, Mailchimp, Sendgrid, etc.).

Internet Service Providers (ISPs) are the ones who provide you with an email address (e.g., Gmail, AOL, Verizon, Outlook, etc.).

The goal of ESPs is to successfully deliver emails to your readers on your behalf and report insights and metrics. On the other hand, the goal of ISPs is to use spam-blocking measures to help sort through incoming emails and identify spam to keep their customers happy. If Gmail didn’t do an incredible job of sorting spammy emails into your Junk folder, your inbox would overflow with spam, and you’d likely look to use another ISP for email.

Simple enough, but from the moment you press send until it arrives in your readers’ inboxes, it can seem like a total black box as to what’s happening behind the scenes. And the truth is, it is a black box, intentionally. ISPs look at thousands of different variables for any given email to accurately determine if it should be classified as spam. If they made these parameters publicly available, it’d be too easy for nefarious senders to game the system.

So what can you do to optimize your newsletter’s email deliverability? In this blog post, we’ll answer these questions:

• How do I avoid the spam folder?

• How do I prevent Gmail from classifying my mail as promotions?

• Why do some readers claim they aren’t receiving my mail?

• What does beehiiv do to ensure the best possible deliverability?

Why Trust Us?

Tyler Denk is the co-founder and CEO of beehiiv – a newsletter platform to fuel creators and publishers' ability to create, monetize, and grow their audience. He joined Morning Brew as the second employee in a role that spanned engineering, product, and growth—responsible for building the renowned referral program and bespoke tech ecosystem that facilitated the company to scale to a successful $75m exit in 2020.

How Do I Improve Email Deliverability?

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While this isn’t an exhaustive list (as mentioned above, there are thousands of potential variables, and they vary from ISP to ISP and person to person), here are some primary factors that ISPs analyze in real-time to determine where to deliver your email:

• Email content — This includes the subject line, pretext, body content, and more. Content is scanned for keywords and phrases that ISPs consider spammy. Examples of this can be large dollar amounts or “porn.”

• IP reputation — Each email is sent from a specific IP address, each of which has its own unique reputation from previous email campaigns.

• Domain reputation — This is the email address you’re sending the campaigns from (e.g., mail.beehiiv.com for us). This also has a unique reputation from previous email campaigns.

• Images — Images previously flagged as spammy or emails that contain too many images with too little text can trigger spam filters.

• Blocklists — If a Domain, IP, and/or URL is placed on a blocklist and your email contains one of these, your mail may be bounced or flagged as spam.

• Recipient preferences — Each recipient has their own additional preferences and spam filters to further make their filters stricter (or vice versa).

• Individual spam complaints — If a recipient has previously marked one of your emails as spam, future emails will likely also be marked as spam for that reader.

There are a few key things to note here…

First, every inbox and every recipient is different.

An email that’s classified as spam in Yahoo may not be classified as spam in Hotmail. Similarly, a reader who uses AOL may receive your email in their primary inbox, while another reader who also uses AOL may receive that same email in their spam folder.

This is due to the different preferences, previous email history, settings, and more. This makes deliverability pretty frustrating for most senders.

Second, some of these factors vary from one email message to another. For example, you may have an incredible IP and domain reputation…but if one particular email contains spammy content or a blocklisted URL, that message can end up in junk. And again, it varies by mailbox provider (MBP) and recipient, so it’s possible to see regular fluctuations in your engagement.

Lastly, the most important thing you can do is build a strong IP and domain reputation. These are a report card of how your campaigns have been performing historically. To understand this, you have to understand both the positive and negative engagement metrics that ISPs look for. These metrics are aggregated at both an IP and domain level.

Positive Engagement Metrics

🔥 email open

🔥🔥 email click

🔥🔥🔥 email forward

🔥🔥🔥 email reply

🔥🔥🔥 move email from spam/junk folder to primary inbox

Negative Engagement Metrics

🧊 delete before opening

🧊🧊messages left unread

🧊🧊🧊🧊 mark as spam

Both positive and negative engagement metrics are weighted differently. While this isn’t an exact science, we used emojis to signify a slightly weighted difference in importance. The reasoning behind this is fairly simple. As an example, let's consider two different senders:

Sender A’s Average Metrics

• 5% open rate

• 1% click-through rate

• 1% spam rate

Sender B’s Average Metrics

• 35% open rate

• 6% click-through rate

• 0.05% spam rate

Assuming all else is equal (email content, images, URLs, list hygiene, etc.), ISPs will favor placing mail from Sender B in recipients’ inboxes and be much more cautious about Sender A. It’s also worth noting that these reputations are built up over time. If you have a single campaign with incredible engagement, that doesn’t mean your next email will automatically be placed in the inbox. It can take months (or years) to build up a reputation with ISPs to show that the domain and IP you’re using to send email is trustworthy and the mail you’re sending is engaging.

So to make a long story short, what are the most important things to prioritize to avoid the spam folder?

1. Acquire quality subscribers who are engaged and explicitly opted-in to your email list.

2. Send engaging newsletters that people are eager to both open and click.

3. Avoid sending emails too frequently or sending them to non-consensual subscribers. Either one could lead to spam & complaints.

4. Churn your unengaged subscribers regularly to ensure a pristine and engaged list (i.e., remove readers who haven’t opened in a while aka “Sunsetting”).

5. Optimize for clicks and replies when possible.

How Do I Prevent Gmail From Classifying My Mail as Promotions?

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The answer is simple (and frustrating) because there is no silver bullet. It requires following the recommendations stated above over a long period of time and proving to Gmail that you deserve to be categorized as an update.

It’s also very possible that your emails, by nature, are more of a promotional type of email. Thus, you may be getting classified correctly.

Why Do People Care How Gmail Categorizes Their Mail?

It’s because some users don’t have an updates tab enabled. So mail that is categorized as an update is slotted into the primary inbox. Alternatively, the promotions tab can be stuffed with e-commerce sales and mailing lists that make it harder to find your mail.

At Morning Brew, we spent years being classified as promotions prior to being moved over to updates. On beehiiv, we’ve seen tons of users initially classified as promotions but move over to updates in just a few weeks.

The truth is—it all depends.

But you just need to control what you can by following the five steps above AND by configuring a custom sending domain. That means that all of your emails send from @yourdomain.com, and that reputation is yours irrespectively of what ESP you use. The sooner you start using a custom domain, the sooner you can build a stronger domain reputation over time.

Why Do Some Readers Claim They Aren’t Receiving My Mail?

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First, double-check that they are actively subscribed to your newsletter. It’s possible they accidentally unsubscribed, so it’s nice to cross that option off the list before throwing stuff at the wall.

Second, ask if their email ended up in spam. As frustrating as it is, it’s possible that your email landed in their junk folder. It’s always good to at least cross that off the list as well.

Third, if they’re using a corporate email, their corporation may have stricter spam filters and block the mail. You can reach out to our support to confirm if that was the issue. If it turns out that is the case, the recipient's firewall administrator will need to change the firewall rules for them to be able to receive your mail regularly.

A Sample Email You Can Send to Readers

For recipients having issues with their firewall blocking mail, we recommend sending the following email to an affected reader:

Hey, your employer and/or network likely has a strict firewall in place blocking our newsletter. You just need to submit a quick request to IT to safelist the following domains, and the issue should resolve itself:

• *beehiiv.com

• *beehiiv.net

• *yourdomain.com

This should be a pretty straightforward request, and IT should know what to do with that information.

How Do You Measure Email Deliverability?

Calculating a delivery score is simple. Just divide the number of delivered emails by the total number of emails sent. Multiply the result by 100 to get a percentage.

For example, if you sent 10,000 emails and 8,500 of them got delivered, your delivery score would be 85 percent.

8,500÷10,000=.85

.85x100=85%

What Is a Good Email Deliverability Score?

Obviously, the closer you can get to 100 percent deliverability, the better. A score of 95 is considered excellent. More importantly, look at data patterns over time. Check your metrics against your own history and industry benchmarks.

What Does an Email Deliverability Specialist Do?

The best way to ensure high deliverability is to work with a consultant. Email deliverability specialists can audit your current setup, pinpoint any problem areas, help you warm up your domain so you’ll be able to send at scale, and advise you on the best way to get your messages into people’s inboxes.

Common Myths About Email Deliverability

Myth: Your deliverability can be ruined by someone else if you share an IP pool.

Reality: Email providers have gotten very good at differentiating between different senders who share an IP pool.

Myth: The goal is 100%

Reality: 100 percent deliverability is just not possible in the real world, or sustainable in any way.

Myth: Being put on a blocklist is the kiss of death.

Reality: While some blocklists like Spamhaus are widely used, not all blocklists have a lot of impact. Also, not all email providers use blocklists. Gmail, for instance, does not use a blocklist. They rely on their own metrics.

Myth: High unsubscribe rates are bad.

Reality: It’s better for a subscriber to leave your list than to complain that you are spamming them. Also, having a clean list of subscribers who enjoy what you send is better than having a large list of subscribers who don’t open your messages. However, persistently high unsubscribe rates will send negative watch signals to MBPs.

What Does beehiiv Do To Ensure the Best Possible Deliverability?

We take email deliverability incredibly seriously because at the end of the day if your emails aren’t reaching your readers, what’s the point of everything else?

Here is a list of the primary things we do to ensure optimal email deliverability:

• Allow configuration of custom sending domains, so you own your domain reputation

• Custom IP infrastructure to ensure the highest quality IP reputation per send

• Integrated 3rd party email validation to ensure legitimate emails on your list

• Strict onboarding verification to ensure quality senders on the platform

• Custom guardrails to flag and prevent and remove poor senders on the platform

• Cross-referenced suppression lists to avoid poor sending practices

• Built-in Gmail clipping warning

• Best-in-class deliverability support team

Want to take your newsletter to the next level? Trust the platform built by people who have a proven track record…Publish on beehiiv.