Email Deliverability

He tried all the things people suggest for properly setting up email deliverability — setting up more mailboxes, spinning up new domains, experimenting with subdomains, not including links, including more links…the whole nine yards.

He still ended up with undelivered emails, spam reports, and poor results.

"I was completely dejected,” Benny said. “My livelihood and my client's livelihood was on the line. I realized I was missing something in my desire to avoid restrictions on my sending. I had stopped acting like a legitimate business sender and started acting like a spammer, spoofer, or scammer."

Benny describes this cast of seedy sender characters: "A spammer is someone who sends non targeted email to get someone to click on something. A spoofer is someone pretending to be someone that they're not. And a scammer is someone trying to trick someone into doing something that they don't actually want to do."

figure 7.1

The path to the inbox — even at scale — became clear.

"If I could just stop acting like a spammer, spoofer, or scammer, I could send a virtually unlimited number of emails and have them delivered safely. That was a major turning point for me."

Today, Benny is now the CEO and Founder of Senders.co, quite literally specializing in helping emails land in the inbox and not the spam folder.

In this book, we’ve taught you the basics for writing the best cold emails of your life — but these efforts won't matter if your email doesn't get through in the first place.

In this chapter, we’ll give you a north star for email deliverability, helping you wade through the copious (and often inaccurate) deliverability advice out there, the hot takes on the future of outbound sales, and the new sender regulations from Google and Yahoo.

You'll learn how to avoid the spam folder by:

• Understanding how modern spam filtering has changed

• Unlearning common deliverability myths

• Properly setting up your cold email sending infrastructure

• Ensuring you're sending wanted, relevant emails

The era of spray and pray is over.

Historically, spam filtering used to be simpler. It was rule-based and focused solely on email content — if you sent “junky” content, you’d land in spam. But today, spam filtering has gotten smarter, faster, and stricter.

Today’s spam filters use highly sophisticated machine learning algorithms that analyze hundreds of data points to identify unwanted emails. They look at what email senders are doing — how many emails you send, when, and to whom — but more importantly, they look at the behavior of your recipients, tracking the rate at which they open emails, click on them, read them, mark them as spam, and more.

This can be a tricky balance to strike. In a LinkedIn survey of over 700 respondents, we found that 60% of salespeople are concerned with these changes to email deliverability heading into 2024.

So what’s the takeaway? The best way to avoid the spam folder is simple, but not easy: be relevant.

It starts with setting up the right foundation for a good sender reputation.

Your business likely has a primary domain (sometimes called a "root" or "main'' domain) that looks something like “companyname.com”. At Apollo, for example, our primary domain is “apollo.io”.

Your main domain is your most valuable asset and worth protecting from spam risk. This is why you need to set up a subdomain and cousin domains, separate from this primary domain, to use for sending cold emails.

1. The subdomain. This exists under the umbrella of your root domain. It uses your main domain, and looks similar, but has an additional identifier to the left like “knowledge.apollo.io”. Despite its relationship with the main domain, subdomains are treated as distinct entities when it comes to email deliverability, allowing for finer control over your sender reputation.
2. The cousin domain (i.e.“lookalike” domain).This is an entirely different domain. Its naming looks similar to your company’s root domain so your prospects instantly make the connection with your company's identity. At Apollo, for example, our sales team sends emails from “apollomail.io” to protect our “apollo.io” domain. For example, if we sent 100,000 emails in one day and something happened to go south, our company’s main domain remains safe. It’s all about risk management.

Assigning separate domains for different mailstreams makes it easier for dips in reputation to be more easily contained. For example: your marketing email tool might get put on “news.company.com”, while the sales email tool sends from “hellocompany.com.” This way, if you get spam complaints or low engagement with marketing emails, for example, your sales team’s vital transactional emails won’t suffer as a result.

Apollo Academy instructor James O’Sullivan ran into this exact issue at a former company, where poor engagement created serious negative ramifications to the primary operating domain.

"I sent myself an email from my work address to my personal Gmail address, just a quick reminder to myself," he remembers. "It went straight to spam. Nobody in that company knew they even had a problem."

So what should you be using for your sales emails? It depends. (We know, we know. This isn’t everyone's favorite answer, but bear with us.)

Sales emails are usually cold, which means they have the lowest expected levels of engagement. As you think about the different ways you send emails, use this chart to determine if your main domain, a subdomain, or a cousin domain is the appropriate tool.

After you’ve set up your new (and old) domains and dedicated them to the right mailstreams, you need to authenticate these domains.

Email authentication tells email servers that you are who you say you are. Similar to how you might use a passport when crossing a border, this is like an ID check to show you're not a spammer, scammer, spoofer, or phisher.

These authentication configurations are usually set by your IT department or domain/mail administrator. If you're on your own or would like to learn more, read on.

There are three key methods to email authentication: SPF, DKIM, and DMARC.

• SPF (Sender Policy Framework). SPF verifies your identity as the sender. You tell mail servers which IP addresses are authorized to send emails on your behalf. If an IP address isn’t listed in that record, the email might be flagged as spam.
• DKIM (Domain Keys Identified Mail). DKIM uses a cryptographic key to add a “digital signature” to your outgoing emails to make sure nothing has changed in transit from when you sent it to when it lands in your prospect’s inbox.
• DMARC (Domain-based Message Authentication, Reporting, and Conformance). DMARC is like the cleanup crew if your emails don’t pass the above. It tells the email servers to accept, reject, or quarantine messages from your domain that don't pass SPF or DKIM checks.

How to set up SPF, DMARC, and DKIM depends on your specific domain. If you don't have IT or technical help and need to do this yourself, search for your domain provider's name and the authentication method to quickly find the relevant help doc. Tools like MXToolbox and aboutmy.email also help you check the current health of your SPF, DKIM, and DMARC.

Yes, this is all rather bland. But this is the kind of technical, in-the-weeds work that separates those who win from those who lose.

So stick with it — your outbound campaigns will thank you.

If you were on the sales side of the internet at any point during the first few weeks of 2024, you saw the buzz around Google and Yahoo’s stricter requirements for sending emails to any address ending in “@gmail.com” or “@yahoo.com” and their associated domains (like “@googlemail.com”).

The change included that all senders must:

• Authenticate their emails, specifically through SPF and DKIM
• Stay under a spam complaint rate of 0.3% lest your domain gets permanently banned
• Validate their domain's domain name system (DNS) records to ensure that your IP addresses are correctly pointing to your domain

Anyone who sends more than 5,000 emails a day to personal email accounts have even stricter rules to follow.

• In addition to SPF and DKIM, you have to authenticate with DMARC
• On bulk sends, you must include a one-click unsubscribe in the email header (refer to figure 7.4) and include a clear* unsubscribe link in the email body content.

And the stakes are high.

The consequences to senders who fail to follow these new guidelines are at risk of their messages being automatically blocked, sent to spam, or even losing their domain.

You might be thinking: “I'm a B2B sender, sending to work email addresses — I can just get by with the bare minimum right?”

Don’t be so sure.

The 5,000-email threshold gets counted at the domain level, so sends from subdomains count too. Google gives this example in their help document:

Lookalikes domains aren’t a viable solution either. Google and Yahoo aggregate data to tie lookalike domains to your organization. Measured across your main domain, subdomains, and lookalike domains, that 5,000-email threshold isn’t as big as it might seem.

Once you're classified as a bulk sender, it's a permanent designation. So even if you don't think you count as a bulk sender, do your due diligence — especially if:

• Your business has a product that allows personal emails for free signups

• You don't have clear visibility into the deliverability health and sending practices behind your promotional emails

• Your organization has agencies, contractors, and other third-party people sending emails on your behalf

• You are including personal email addresses in outreach

Making it hard to opt out of emails just means you're making it easier for your recipient to hit the spam button instead.

So don't make them jump through hoops to unsubscribe. Make it as easy as possible to opt out from future messages by including a simple unsubscribe link in every email. If you'd like to add the option or fall under the bulk sender designation, set up a one-click unsubscribe in your email headers.

Unsubscribe links show you as honest and reputable (not to mention, required by law in many places). Consider them a gift to both you and your recipient. You'll get to "spend" your emails on more promising recipients if they opt-out.

Google's Postmaster Tools are a free tool to help you monitor deliverability metrics, like spam rate, domain reputation, IP reputation, and more.

We'll get more into spam rates later, but since Google doesn't report user-reported spam rates to email service providers, Postmaster Tools is the best place to get this information.

A custom tracking domain is an additional domain (or subdomain) that helps you gain insights into your email performance, like opens and clicks. When someone clicks on a link in your email, the request goes through a tracking service, which logs the click, before landing on the destination URL.

Organizations that send sales and marketing emails often use platforms like Apollo or HubSpot, which will have in place a shared tracking domain for their customers to use.

For optimal deliverability, set up your own custom tracking domain so your deliverability isn’t affected by the actions of others.

Email metrics like opens and clicks tell you how your campaign is performing and show MBPs that your emails are actually wanted.

Open tracking, which indicates whether or not people are opening your emails, can help you suss out if you’re getting through at all. If you see a significant and lasting drop in your open rate, there’s a good chance that you're having trouble reaching the inbox.

When John Kim started his company Paraform, he followed best practice, purchasing additional domains, “getparaform.com” and “useparaform.com”, to protect his company’s main domain as he scaled up his outbound email motion.

“As an early-stage startup, we didn’t want to get banned while we refined our volume strategy,” says John.

But fresh domains aren’t a free for all. John patiently waited a few weeks before sending any emails so he didn’t look like a trigger-happy scammer. Then, he started warming up his inbox.

40 emails per day per inbox.

It was far less than Google Suite’s hard limit of 400 emails/hour and 2,000 emails/day. He slowly increased that volume over time.

More and more emails landed into inboxes, without negative impacts on their domain, and open rates skyrocketed to 83%.

John used Apollo for warming up his domains and setting sending limits, but there are two ways you can go about it:

• Automated, or bot-driven warm up, uses bots to simulate email engagement.

• True or human-driven warm up is a process of slowly ramping up the number of emails you send over a period of time.

Bot-driven warm up tools are a tempting option. They can help you quickly establish a positive sender reputation by simulating positive email interactions from controlled or seed email accounts. Why not let the machines handle it, right?

But, unfortunately, mailbox providers are primed to detect when bots are pretending to be recipients, which means a slightly more manual, human-led approach is often the better bet. Especially if you’re dealing with only two to three new domains.

Here's what we recommend:

• Plan to gradually increase the volume of your email sends in the first couple of weeks of using your new domain. See figure 7.6 below for an example schedule.

• In the beginning, send to real people that you know — friends, family, old co-workers.

• If you're out of personal contacts to reach out to, keep your sales game going (slowly!) by targeting recipients who are the most likely to engage (due to previous engagement history with you or your company, or via other data signals) and sending the most personalized content you can muster.

• Ask questions to get more responses.

• Ask your closest contacts to respond to your emails and mark them as important.

• Increase volume only when you see positive engagement signals like opens and clicks. Not seeing these signals? Update and personalize your emails further.

• If you don't see engagement, pause and review your approach and adjust as needed.

• Use technology to help schedule and rate-limit your sends or even to make real-time adjustments based on key performance indicators.

• If your deliverability score remains low, we recommend you continue to warm up your inbox until it improves. If you're using Apollo, we'll track this and provide tips to improve your deliverability score.

Every mailbox provider has daily and hourly sending limits.

While that sounds easy to abide by, there are also additional (unpublished — very sneaky) limits that take into account factors related to your sender reputation and behavior, like:

• Age of your mailbox

• Total recipients per day

• Type of content in your messages

• And the number of spam reports you've received

The providers are watching out for spammers, spoofers, and scammers, so they are monitoring email send volume to make sure you’re a “regular person.” The average, non-salesperson doesn't send more than 50 or so emails a day, even if they're incredibly active. They also don’t send all 50 emails at the same time — they spread them out throughout the day.

You need to mimic that “regular person” email behavior.

Set limits for your outbound mailboxes and campaigns to gradually increase sends as you're building your sender reputation (the limits are always lower when you're starting from scratch!). Google recommends that you:

As you scale your outbound email program, think of it more like a drip rate instead of a periodic flood – consistent and frequent versus large surges.

At first, you should be sending no more than:

• 50 emails a day (more if your campaigns are seeing >5% reply rates and you have a high domain reputation)

• Six emails an hour

• With a delay of 600 seconds between emails

When Apollo’s Head of Marketing Automation Cole D'Ambra headed up Ashby's automated outbound program, he ran into a deliverability health emergency right from the jump.

“We ran into spam issues almost immediately after launching because we weren't able to control the rate of delivery out of our mailboxes with HubSpot,” he said. “If you wanted to sequence 100 people from a single inbox, the only way to do it automatically was for all 100 messages to leave at the same time.”

The other option was to sit there and manually send messages out every couple minutes. And who has time for that?

Eventually he moved those campaigns to Apollo and set sending limits to control how many emails got sent per day and per hour, including an ideal 90-second delay between the sends. No surprise — deliverability improved and so did the results. Ashby increased their email sends by 50% while also increasing inbox placement rates from 62% to 96%, open rates from 32% to 51%, and landing 560% more replies.

Cole shares, "People always want to know how many emails you can safely send. My response is: you should send as many emails as you can that feel like they were sent one-to-one."

Sending limits help you do that.

You've set up your new domains, authenticated them with the email service providers (ESPs), and created guardrails to keep you on the right track. Everything after a good setup comes down to relevant email copy — and relevance is in the eyes of your recipients.

We cover how to be relevant in multiple spots in this book, including the chapters on prospecting, cold emailing, and running multichannel outreach.

Here, we'll focus on a few tactics to ensure that relevancy supports healthy email deliverability, too.

Start by making your lists as small as you can. If you're doing account-based sales, send to specific roles, narrowing down who you reach out to within a company as much as you can.

The good news is: you've done a lot of this work when you built your targeting framework. Now, review that framework through the lens of how you'll use it for outbound emails (see figure 7.8).

Prospects don’t engage with messages they feel were sent in bulk. People can spot a lack of effort and tend to respond in kind.

Use meaningful personalization to increase the chances your audience feels that human-led one-to-one-ness. And be careful of where and how much you automate that personalization. While automation helps you sell more efficiently, when deployed poorly, it can make it too easy to send the same kind of emails to lots of random people. And that’s the fastest way to land in the spam folder.

"You have to be strategic in how you're approaching automation, because if three people [in 1,000] mark you as spam at the same company, your domain is ruined," warns Lindsey Boggs, VP of Sales Development at Glassbox. "As much as automation helps us save time, it can also suppress us getting in the inbox, period."

Remember: the higher-value your prospect, the more manual your personalization should be. For your other prospects, as long as you are fine-turning your lists to be as targeted as possible and tightly tailoring your sequence messaging, it can still give that 1:1 feel without all of the research and preparation.

Just like with your physical health, there are vital domain health signals you need to keep an eye on.

First and foremost, your spam rates. Mailbox providers measure spam rate as the percentage of messages flagged as spam by users of messages delivered. At the time of writing, the hard and fast rule according to Google is: if your spam rates go above 0.3%, your mailbox will be suspended.

There’s no “hack” to a good sender reputation — it’s built on multiple dimensions over time.

Much of the popular advice about email deliverability out there is based on misconceptions and outdated practices of trying to game the system. If a tactic sounds like a silver bullet without any nuance, it's likely not great advice.

Let's debunk a few myths right now.

Consider all the marketing emails in your inbox right now. The vast majority of them probably include links, images, and HTML. Clearly the mere presence of a link, an image, or HTML is not what sends a message to the spam folder.

Spam filters aren't specifically looking for links — they are looking at how the links impact your recipient's opinion of your message. If MBPs see your link in a lot of spam complaints, then the link's domain can become a red flag to the filters.

In many cases, links actually support relevancy. Links to landing pages, relevant content, or, even your calendar, can support the customer journey. Link clicks also show positive engagement to mailbox providers.

The context, setup, and reception to your message with the link matters, and this extends to any advice around individual elements. Links, images, HTML, and signatures aren't individually going to trigger suspicion, but if those things make it more likely for recipients to mark a message as spam, that's when you run into deliverability issues.

The mere presence of a tracking link doesn’t automatically put a message in the spam folder, but you’ll want to take steps to mitigate the negative impact that tracking could have on your deliverability.

The best way to do this is to set up a custom tracking subdomain. You can feel more secure that link-tracking won’t damage your sender reputation with this step in place.

In fact, it's quite the opposite: low engagement is the cause for bad deliverability.

The MBPs learned long ago that it's easier for machine learning to identify what people treat like spam than it is to identify what is spam based on its own attributes. If your emails are underperforming, it’s much more likely that your problem lies with poor targeting, irrelevant content, or boring copy.

In Cole D'Ambra's experience, "The biggest mistake people make is not monitoring for potential issues and then when things go poorly, they blame it on deliverability. In reality, maybe the list isn't good or you're moving outside your ICP."