Boosting Gmail Deliverability: Tips From an Inbox Pro

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Hi, I’m Chris Arrendale, CEO and Principal Deliverability Strategist at Inbox Pros. We help brands and marketers on issues like inbox placement, deliverability, reporting analysis, and remediation.

My friends at BriteVerify invited me to tackle a pressing issue: Gmail’s focus on engagement is keeping too many marketing emails from the most popular inbox in America.

Why Engagement Matters

If Gmail’s algorithm thinks a marketing email won’t be engaging enough to a user, it won’t deliver that email to the user’s inbox tab. While Gmail doesn’t have anything against marketing per se, its ongoing fight against spam and phishing messages can ensnare well-meaning marketers.

In fact, engagement isn’t just a Gmail problem. Although the service doesn’t share its algorithms, its practices influence Outlook, Yahoo, and the entire ecosystem of Internet Service Providers. Marketers who don’t master Gmail engagement could eventually find themselves shut out of other inboxes as well.

How Google Measures Engagement

Gmail keeps the details of its engagement filters a secret, and it updates them all the time. However, we do have a pretty good idea of factors Gmail uses to measure engagement.

Note the plural “factors”: there’s a misconception that a single word in a subject line can get your email relegated to junk. In fact, Gmail’s measure of engagement depends on many things like:

Email Opens

This one is fairly obvious – people who open your email probably find it more engaging.


Any kind of click inside of an email is good – even a click on the unsubscribe button. True, a high unsubscribe rate may mean your content is off, or you’re sending to the wrong people. But from Gmail’s perspective, all clicks inside an email look the same.

Moving an Email To a Different Folder, Starring, or Tagging It

These types of organizational moves show Gmail that a user is engaged.

Marking an Email as “Not Spam”

Moving your email from the spam folder to the inbox is very positive for engagement.

Replying to a Message

This is clear evidence of interaction with a brand.

Adding an Address to a Whitelist or Address Book

This is helpful, but few people do it these days.

Deleting Without Opening

This factor is obviously negative for a brand’s reputation, especially if a user deletes messages from the same address repeatedly.

Reporting Spam

Unlike Hotmail, Yahoo, AOL, and others, Gmail does not provide a traditional feedback loop about who clicked the spam button. Therefore, Email Service Providers may not suppress the Gmail addresses of those who marked the message as spam. Thus, the ESP will keep sending emails, and they’ll go directly to the junk folder. Once there, the message is unlikely to get opened or clicked, hurting a brand’s engagement.


Our testing shows that if a brand sends emails that get ignored, its emails may start to go to the junk folder. Gmail thinks “Well, I guess the user doesn’t want this message.” It’s kind of thinking for you to tidy up your inbox.

Phony Engagement

Gmail has data about the devices people usually use to open emails and the location where they usually open them. If they start to see anomalies, they may assume the account has been hacked, or that it’s a dummy account for faking engagement.

How To Get Better Deliverability

Stay Consistent

Make sure to have what I call “deliverability branding”, such as a consistent name that people recognize and a subject line that actually references what the email is about.

Marketers often panic if they start to see emails go in the junk folder. They’ll do things like change the from name or change the from domain. The problem is that it makes things worse.

ISPs like Gmail, Hotmail and AOL like consistency in things like the sending domain, bounce domain, from name, postal address, footer, and privacy policy.

Don’t Send Too Much Email

Yes, email is the cheapest, most effective form of marketing communication. But some marketers may think that simply sending more emails is the key to engagement.

I’ve spoken to clients or prospects that say “If we send a million emails, we make $500,000. So if we send two million emails, we’ll make $1,000,000.” That math may have worked in high school algebra, but from a business perspective, it creates list fatigue.

Some brands might say they’re going to send a user one email a week, and that one email turns into two, then three, then five, then seven. Why? Maybe the brand had a bad quarter. Maybe they’re struggling financially and they want to get more out of their email list. This is short-sighted: they’re not looking long-term at the effect on their reputation.

Send To Properly Verified Emails (That Actually Exist)

When collecting emails on a website, you can use tools like BriteVerify that will auto-verify that an email address exists as the user is typing it. I would also stress the importance of maintaining other best practices such as opt-in confirmations and setting proper expectations.

Clean Your List of Inactive Emails

Tools like BriteVerify can integrate with some ESPs to filter out addresses that have been inactive over the past three, six, or twelve months.

Try to Re-engage One More Time

Don’t just remove inactive email addresses without trying to re-engage with them, perhaps through a separate domain/IP set up specifically for re-engagement campaigns. You might send three emails. The first one may be an okay offer, the next one may be a good offer and the last one may be the best offer before you say goodbye to the address.

I often find that when emails hit the inbox but don’t get engagement, recipients say things like “The offer wasn’t good enough” or “I’m no longer interested”. Many of these email addresses already receive lots of emails and suffer from being “email drunk”.

Everybody today gets so many emails. That’s now the number one reason why people complain and mark an email as spam. You have to work hard to stand out in this environment.

Don’t Get Emotional About Dumping Email Addresses

Marketers may realize that dropping inactive emails is a best practice, but they feel pressure from their executives to grow their list and send more email.  To those marketers and their executives, I say “trust me.”

We’ve seen instances where brands cut their lists and then open rates, click rates and conversion rates go up.

First, cutting disengaged users means the remaining engaged users make up a bigger share of a smaller pie. Moreover, high levels of disengaged users could be affecting inbox placement for everyone. After removing disengaged addresses, inbox placement could go up, leading to more people clicking and converting.

More Than a Set of Rules

Sending more engaging email isn’t just about dutifully following a set of rules. It’s about an attitude of respect for readers and a desire to truly connect with them. After all, Google’s policies aren’t arbitrary. They are designed to make email a better experience for its users. And that means marketers who are engaging will have a better experience, too.