Email deliverability = good fundamentals.

Not sneaky tactics.

If you have a few hundred, thousand, or even a few tens of thousands of subscribers and you send once a week, email deliverability should not be a primary concern.

Writing really good emails and newsletters (and growing it) should be.

The reason is complicated, and I’ll get into it, but for now, know that if you’re a startup with less than 50,000 or 100,000 subscribers and aren’t sending super frequently, then a lot of the fancier email deliverability stuff won’t really apply.

But, what matters for everyone?

The most important thing you can do for deliverability and overall newsletter health and growth is to ensure that people consistently:

1. Open your emails
2. Click on links in your emails
3. Reply to your emails
4. Stay subscribed
5. And don’t mark your emails as spam

These are really the most important things—and the hardest to achieve.

Clever hacks will not make up for “meh” or spammy content.

The best way to achieve those things is to:

1. Consistently make it one of their favorite newsletters.
2. Not bombard them with so many emails they can’t keep up.
3. Remove people who aren’t engaged anymore.
4. Let people unsubscribe if they want to (so they don’t mark you as spam).

Someone should be excited to see your emails in their inbox and then open and read them.

If you fail to do that, you are not only shouting into the void, but your deliverability will decline over time. And all the “clever tricks” won’t help you.

Beyond that, you want to make sure you’re not sending emails to:

1. People who don’t want it and can’t unsubscribe
2. People who are not opening or clicking your emails anymore
3. Broken, invalid, or abandoned email addresses
4. Spam traps (more on this later)
5. Low-quality email addresses (ones with poor reputations)

Before I give more specific and general advice, let’s get some of the foundational stuff out of the way:

How does email deliverability work?

And why does it matter?

Good email deliverability enables your emails to land in recipients’ inboxes, something known as inbox placement.

This journey isn’t as straightforward as you might think. Here’s what happens whenever you send an email through an email platform:

1. You click send.
2. Most of your emails are sent. Some are suppressed—they’re prevented from being sent to recipients based on previous activity, like a hard bounce or spam complaint from that specific user.
3. Most of your sent emails are delivered, except for those that soft bounced or hard bounced.
   1. A soft bounce means an email couldn’t be delivered because of temporary reasons. A few examples: The recipient’s inbox is already full; their mail server has an issue; or your message was too big for the recipient’s inbox.
   2. A hard bounce happens when you send an email to a mailbox that doesn’t exist. This could be because someone entered their email incorrectly, they used a fake email, or they changed jobs and the email no longer exists.
4. Your delivered emails can then go in one of a few directions:
   1. They arrive in the recipient’s inbox—these are the emails that count toward your campaign’s deliverability rate.
   2. They land in the recipient’s spam or junk folder. This is dictated by an algorithm and is based on your sender reputation and the contents for your email.
   3. They fall into a spam trap. These are fake email addresses used by ISPs and blacklist providers to catch unethical email marketers.
   4. They’re blocked completely by an ISP due to high rates of spam to other email addresses managed by that ISP.

Wait what’s an ISP? Well here are two acronyms to understand:

• Internet Service Provider (ISP): The companies that not only give people internet access but also provide mailboxes, like Gmail, Outlook, Comcast, and Yahoo. You can think of ISPs as inbox gatekeepers. They decide if you get into the inbox.
• Email Service Provider (ESP): Tools marketers use to send emails to their subscribers. Think Mailchimp, Klayvio, ConvertKit, Substack, Beehiiv, Customer.io, and Drip.

Why it matters less if you have a smaller list

For basically all ESPs (Email Service Providers), unless you have a massive list and send a ton of emails, they’re almost certainly sending your emails on what are called “Shared IP Pools.”

Essentially, the email provider sends your emails using the same server they use to send other customer’s emails.

If you have a large list and send millions or billions of emails, you’ll generally shift to have a “Dedicated IP,” meaning there’s a specific server that sends on your behalf.

So on a Shared IP pool, the reputation of the server is not just impacted by you, it’s impacted by every other customer that is using that ESP.

There are some benefits to this:

1. To maintain a good reputation you need to be sending at least tens to hundreds of thousands of emails per week. So if you’re below these large thresholds it’s better to be lumped together.
2. If you’re going to send an email to promote your product, it’s great to use the Shared IP Pool since any negative feedback you might receive will be directed at that shared pool instead of your own. (More on this later.)
3. You’re not solely responsible for the reputation so it’s less important to do things perfectly.

But it’s not that simple.

It’s safe to assume that the email tool is monitoring your email’s activities. And that they may have Shared IP Pools with better reputations than others. And that they’d send emails on behalf of their best customers using their best IP pools.

And if you’re getting a lot of spam complaints or hard bounces, they may just remove you from their platform entirely.

So it’s still worth taking it seriously. Just less so than if you have a Dedicated IP.

General advice for everyone

With that out of the way, let’s dive into both general and nuanced advice for everyone (regardless of list size).

After that, I’ll give some advice for people on Dedicated IP pools (again, ~100,000+ subscribers.)

Everyone should do this:

• Try to make your newsletter someone’s favourite
• Make sure your emails are optimized for desktop and mobile
• Survey people in each newsletter edition and improve it based on feedback. These links take them to a super quick Typeform survey:

• • Some email tools have native ‘polls’ features that allows you to gather feedback directly.
• Encourage replies by asking questions
• Make it easy for people to unsubscribe in every email
• Allow people to unsubscribe to certain types of emails (promotions, drip emails, product-specific emails, etc).
• Write compelling copy that encourages clicks
• Periodically or automatically remove people who:
  • Have received > 20 emails without opening
  • Have had emails hard bounce
• Don’t slam your list with constant promotions. Treat it with care.
• Only email people who have consented to receive them.
  • Do not buy email lists
• Segment your audience list and send emails to those most likely to find it valuable. For example, they’re in a specific funnel, have clicked on certain pages, have purchased certain products, or fit the intended target demographic (you’ll need to ask for that data).
• Use email validation tools like Kickbox to verify that an email is valid, deliverable, and decent quality before actually subscribing people to your list.
• Give single opt-in a chance if you’re willing to practice good list hygiene.

More on that last point in a second.

Specific advice for everyone

Now the more nuanced stuff.

Single vs double opt-in

A lot of people will advise that you should only subscribe someone to your newsletter if they confirm the subscription by clicking a “confirm link” in the welcome email.

This is a great way to ensure only people who want it get it. Therefore, it’s a good way to ensure you have a better sender reputation over time.

But a decent chunk of people who want it will never get around to opening that welcome email and clicking the button.

So it’s a trade-off: Growth vs deliverability

Here’s the recommendation:

1. If you will periodically monitor your email metrics, use email validation (more on this later), and clean your list to remove problem folks (bouncing, not opening, etc), then single opt-in will help grow your email list faster.
2. Double opt-in is the safe bet if you’d rather just focus on writing good emails.

💡 What we do is we use the email validation tool below. We only add people if they’re considred “deliverable.” And if the email address is from a low-ish quality provider like yahoo, aol, or hotmail (which are commonly used in spam attacks), we require double opt-in. For most other users we just do single opt-in and purge accordingly.

Email validation

One great way to keep your list clean is to use an email validation tool like Kickbox.

It’ll spit out whether the email is deliverable (it’s not fake or broken), whether it’s “low quality” and whether it’s likely a spam trap.

You can then only subscribe someone if they pass that bar.

It does cost money, so if you’re on a tight budget:

You can YOLO it and send emails to anyone who subscribes.

For anyone who is not opening their emails, you can just run them through Kickbox to see why.

Segment out weird emails

You can create segments or filters for things like:

• Common misspellings/typos: gmail.co, gmail.con. neal@gmail.con
• Invalid emails: No @ or .com. neal@gmail
• Admin inboxes: Like help@ or info@ or contact@. help@gmail.com
• Test emails: test@, test.com, abcd@, 123@

Or you can just manually go through the list to see stuff like that.

Then you can unsubscribe them or just not send to them.

Sunset segment + win-back campaign

If someone goes 20+ emails or a few months of receiving your emails without opening or clicking them, you should consider unsubscribing them.

You should create automatic/manual segments in your ESP for people who fall into this camp.

Before you unsubscribe them, you should try a win-back campaign—one where you email them specifically trying to get them to open, click, or reply to your emails.

We do this in a 5 email sequence (trying various different subject lines, senders, and angles) where the whole goal is to get them to open and click. For example:

If someone goes the whole 5 emails without opening or clicking, we remove them from our lists.

Dedicated IP Stuff

Below are things you can only do if you have Dedicated IP and want to get really complicated. Definitely wait until you have 50,000 or even 100,000 plus subscribers to add this complexity.

Warming it up

When you start a dedicated IP, you can’t just start blasting off your 100,000 subscriber newsletter right away since you have zero reputation. Email providers will immediately halt you.

Instead, you need to slowly warm it up. Start off by sending 200 emails and double volume each day (200, 400, 800, etc.).

Luckily email tools will often help by doing this on your behalf in the back-end.

Custom Subdomain

If you’re sending a newsletter, marketing drips, promotional emails, and transactional emails (purchase confirmation), then you’ll likely want separate Dedicated IPs for each one.

To do this, you’ll want to create separate subdomains for each one. For example, for a long time we did:

• Newsletter: n.demandcurve.com (dedicated)
• Marketing (drip emails): m.demandcurve.com (dedicated)
• Transactional: t.demandcurve.com (we actually have this on a shared Transactional Pool from our email tool that has really high deliverability)
• Promotional: e.demandcurve.com (shared IP)
• Covert emails: demandcurve.com (shared IP). This is for emails I want to make it look like I actually sent them manually.

Note, now we made it more simple and just use shared IP. So we only recommend above if you're a very high volume sender.

That way the reputation of the newsletter is not damaged by the reputation of the promotional emails or marketing emails.

To do this you’ll need to set up DNS records for each subdomain. Most email tools will walk you through this process as they need to give you the specific data to add to the DNS records.

Email authentication

Whenever you send an email, ISPs check the IP address to see where it came from and to confirm that your IP has permission to send emails from your domain.

The point of this is email authentication, which helps ISPs prevent fraudulent email activity like phishing attacks.

Email authentication is a must when using an email tool to send messages on behalf of your custom domain. It involves a few protocols:

• Sender Policy Framework (SPF) lets senders define which IP addresses can send mail for a particular domain.
• DomainKeys Identified Mail (DKIM) attaches a digital signature to outgoing emails to confirm that messages aren’t fake or edited.
• DMARC builds off of SPF and DKIM for extra security. It lets email senders specify to receiving servers how to deal with emails that don’t pass the other methods of authentication—like send them to the junk folder or block them.

Some ESPs automatically provide authentication. For example, any domains bought through Mailchimp have DKIM enabled by default; but if you got your domain through another provider, you’ll need to set it up. Ultimately, how authentication works depends on your chosen ESP.

Fortunately, most ESPs offer clear instructions to walk you through the process. Here are resources from a few of the biggest ones:

• Mailchimp
• Campaign Monitor
• ConvertKit
• Customer.io
• Drip
• HubSpot
• Klaviyo
• Rejoiner

Again, focus on the fundamentals

That’s really the 80/20 to email deliverability. Here’s a quick recap:

The most important

1. Make amazing content that people love
2. Stay focused on a particular topic/audience (if you hard pivot then you’re emailing people who don’t care about this new topic)
3. Don’t send so often that people can’t keep up
4. Only email people that want to be emailed by you
5. Treat your email list with care and don’t hammer them with promotions. Be sparing and segment your email list so you only hit those interested in something.
6. Survey your audience and keep writing better and better emails.

Once you’ve done that then:

1. Practice good list hygiene
   1. Remove invalid, low-quality, or bouncing emails
   2. Remove unengaged folks
   3. Do email validation
2. Worry about the single vs double opt-in strategy

And once you have a really large list then:

1. Switch to Dedicated IP and warm it up
2. Create numerous subdomains for different purposes