ISP Deliverability Guide: Gmail

Launched over fifteen years ago, Gmail has grown from the "new kid on the block" into a position of prominence. Depending on what data you look at, you might even see Gmail as the #1 mailbox provider, at least here in the US.

Gmail's spam filtering systems incorporate user feedback and engagement. And they know what they're doing. If you are not sending wanted mail to people who requested that mail and who read that mail at high enough percentages, you're going to struggle. You won't reliably get your mail to the inbox. Their systems are too good -- their magic spam fighting robots look at metrics very closely -- and their view of certain metrics can even change over time! What got you to the inbox in 2016 might not be good enough to get you to the inbox in 2020. Deliverability success at Gmail requires not only that you adhere to best practices, but it also necessitates ongoing monitoring and tweaking of your marketing program.

Spam Resource Top Five Deliverability Tips for Gmail:

1. DO enable DKIM and SPF authentication. Sender Policy Framework (SPF) is a simple DNS record that conveys what IP addresses are allowed to transmit mail for your domain. It's easy to configure and there's absolutely no reason you shouldn’t have already implemented SPF. Domain Keys Identified Mail (DKIM) is a little bit trickier. Your (or your ESP’s) outbound mail server needs to support DKIM directly; it involves signing outbound mail with a cryptographic key. You don’t see a message’s signature by default; it’s stored in a hidden header. But the receiving ISP (in this case, Gmail) uses that to ensure that the mail was truly from the domain name it claims to be from. (That’s a simplistic definition that any handful of email geeks will take issue with, but I’m going to stand behind that and say “that’s what it boils down to.”) Mail that lacks SPF and DKIM authentication is going to be more closely scrutinized by various filtering steps at Gmail. It’s not the only determining factor in inbox placement by any means, but it definitely matters.
2. DO enable TLS. Back in 2015, Google warned that they were going to eventually highlight mail sent over unencrypted SMTP connections. They started doing so in 2016, adding a scary "unlocked" icon to messages sent over SMTP connections that don't utilize Transport Layer Security. The reality of the situation is that Google is pushing email senders to make it harder for bad guys and governments to monitor email in transit. I don't think sniffing unencrypted marketing mail is that useful to either bad guys or governments, but if you don't get rid of that little "unlocked" icon, your subscribers will probably start to wonder about you. So do it. Enabling TLS is typically pretty simple-- it's already supported by almost all mail server software and typically just needs to be enabled. There's little to no downside nowadays.
3. DON'T focus on "Promotions" vs "Updates" tab placement. Google wants to place marketing mail in the "Promotions" tab and trying to outsmart them is something you'll possibly get away with in the short term, but not in the long term. Google likely notices mis-categorized mail and any workaround will probably stop working after their next system update. Instead, focus on sending wanted mail and subscribers are going to read it regardless of what tab it shows up in. (And keep in mind, whichever tab it is under, it is actually in the inbox.)
4. DON'T buy or rent lists. Google is very sensitive to feedback from Gmail subscribers. Send mail to a purchased list, and enough people will mark that mail as spam, and Gmail's filters will pick up on that and then all your mail goes to spam. Cleaning up after you fall into this trap takes time and is not fun. There is nobody we can call at Google to get them to give you a do-over and reconsider your lack of inbox placement. Sure, we all know people at Google, but they aren't willing to take those calls, because they think the filters are working as advertised and you're getting the deliverability you deserve.
5. DO focus on engagement. Gmail's filtering is heavily engagement-driven. (You will occasionally find a marketer who swears otherwise, but they're full of beans. I am not.) If you're struggling to get solid inbox placement, a common fix is to adjust who you're sending to so that you are mailing only subscribers who have opened or clicked in the past eighteen months. Do that for your next three-to-four weeks of mailings and that will likely result in you getting solid inbox placement, and should keep your mail out of the spam folder. (If your mail truly is wanted by your subscribers.) Then you have to decide what to do about the rest of your subscriber base, the people who aren't responding. There's a potential for strategy there that goes beyond the scope of this simple blog post. Talk to your friendly neighborhood deliverability consultant to figure out how best to handle this.

Bonus Tip

DON'T look to a technological solution to fix a permission problem. Almost all of the time, the reason a sender's mail is going to the spam folder is because that sender didn't fully follow best practices. There isn't some a header or code you need to add that will fix a deliverability problem caused by low engagement or a lack of permission. Sure, occasionally an ESP or email platform will mess something up, and you should definitely work with them to check to see that SPF, DKIM, bounce processing, and all that other stuff are working properly (see Gmail's Sender Guidelines to learn more). But let's be clear -- it is rare that a technical failure is the source of a deliverability issue.

Contacting Google

Google does have a submission process (click here), where you can go and submit a sample message, state your case, and request that they reconsider spam folder placement (or blocking) of your messages. Use it. But only AFTER you're sure that you're doing everything right. If you're buying lists or trying to email people who haven't responded in years, you're wasting your time. But if you ARE doing everything right, and you think Google is unfairly filtering your messages, they do offer this review process.

My experience is that they will not respond. If they believe that your issue does merit an adjustment in their spam filters, look for that to happen in around fifteen days. Watch your deliverability metrics for any improvement after that period of time. If things improve, they likely did take action. If not, they likely do not think action is merited in this case.

Google Postmaster Tools

Google has a reputation portal called Google Postmaster Tools, often referred to as GPT by those of is in the email industry. Register your domains here and you'll get some varying level of information about your domain and IP reputation and in some instances, this will help you identify problems that need your attention. Not always -- the data can occasionally be a bit cryptic -- but it is what it is and you should check it out to see what benefit you can glean from it. Here you'll find Google's support page for GPT.

Learning More

Want to learn more about Google's Gmail filters? Laura Atkins from Word to the Wise has got you covered.

Click here to view the whole series of Spam Resource ISP Deliverability Guides.