How to avoid the Gmail spam filter

Spam Filters are Getting Smarter

Back in February, Gmail announced that they were blocking an extra 100 million emails per day using AI, powered by TensorFlow, an open source machine learning platform. While this amounts to 1 extra blocked email per 10 users, it brings the age old question of how to get around spam blockers back into the spotlight. Gmail’s adoption of AI means that spam filters can be personalized to each user. Translation: it’s even more important that you’re not only cleaning your lists, but creating content that resonates with your reader base.

Spam Filter Basics

First and foremost, you need to make sure that you have a strong reputation score (this impacts deliverability). Three key practices for deliverability are:

  1. Create a permission-based list
  2. Create relevant, engaging content
  3. Optimize your email content (and lists) for high engagement

While these are the three golden rules regarding deliverability, it can be a little more nuanced. Download the Email Deliverability Guide for more information.

You Might Hit a Spam Filter If…

While every ISP is different, there are a host of factors that can cause your messages to be flagged as spam. Before doing anything else, make sure that you are using proper authentication and that your IP reputation is good. Secondly, you want to ensure you have a healthy, clean list since metrics like bounces, spam complaints, and unopened emails have a direct impact on your reputation, which in turn can cause you to get flagged as spam. Lastly, avoid these formatting faux pas:

Using a wide array of font sizes (especially larger than 12pt), styles, and colors
Using all uppercase letters
Linking out to several different domains
Using exclamation points (or numbers/symbols to spell out words) in the subject line
Using images with a large file size

Gmail-Specific Spam Indicators

While we can’t account for how AI impacts which emails get caught in spam filters, you can lower your chances by ensuring standard spam flags aren’t being thrown. Here’s just a few of the things that Gmail keeps an eye out for:

Content — Stay Away from Spam Triggers

While this tends to be a less common problem, if your email content contains too many spam trigger words, Gmail could be sending your emails to junk or deleting them all together. Words like: “#1”, “Will not Believe Your Eyes”, “Why Pay More”, “This isn’t Spam”, “This Won’t Last”, etc. can be flags that your email actually is SPAM. However, remember that context is everything. Choose your words carefully and you’ll be just fine. Check out a list of possible triggers here.

Links — Know What Sites You Are Sending People To

It’s important that you know the reputation of sites you’re sending your readers to, so make sure to do your due diligence before throwing in a link. Links to blacklisted sites can cause your emails to be sent to SPAM.

Source — Shared IP Addresses Gone Wrong

If your email marketing platform uses shared IP addresses, your stellar reputation could be dragged down by other companies on your shared server. Many ESPs have strict policies regarding sender reputation on shared IPs, while other companies will use dedicated IPs to avoid this problem (hint: WhatCounts is the latter). When selecting your ESP, it’s important to vet this area as it could have serious implications down the road.

Header Inconsistencies

Inconsistencies in your “From,” “Reply To,” and domain can get your message flagged as SPAM. Make sure all three of these fields match to boost the probability that your message will be delivered successfully.

Engagement — Send Relevant Content to the Right People at the Right Time

It may be tempting to send every single email to every person in your database. After all, the more inboxes your email arrives in, the more opportunities for people to engage, right? Wrong. ISPs are increasingly looking at engagement metrics (who opens or clicks on an email) to make decisions about which emails get filtered as Spam or deleted as junk mail. Take the time to clean and segment your list (check out this article on list cleaning) and create relevant content to send to your customers and subscribers.

Do You Have a Gmail Deliverability Problem?

If you think you might have a deliverability problem, there are ways to bring your reputation back up to snuff, but first you need a diagnosis. One easy way to check your deliverability by ISP is to compare your engagement rates by service provider. If you notice that your open rates for Yahoo, Outlook, etc. are around 20%, but your Gmail open rates are sitting at 3%, chances are you have an issue. Using the information above, you can quickly determine whether you’ve been partaking in behaviors that will get you thrown into the spam pile and you can pivot accordingly. However, you’ll need to take action to rebuild your reputation beyond these standard practices.

For starters, ask your engaged subscribers to add your “From Address” to their Gmail list of contacts and consider reminding them how to set rules in Gmail to categorize your email as “not spam” if found in the junk folder. Other things you can do include creating an easy unsubscribe process, a double opt-in subscription process, and swapping to a dedicated IP address and private domain (recommended). If you’re still struggling or want more information on how to increase deliverability, our Deliverability Experts are just a call away. We can work with you to diagnose the problem and create a strategy to boost your reputation and get you back on track — just reach out to get started!

More to explore…


Apple Mail Privacy Protection

What is Apple Mail Privacy Protection? Apple Mail Privacy Protection (MPP) is a feature available to Apple Mail users. MPP protects a user’s privacy by

Read More »

Media Manager upgrade

You may have noticed that your preferred browser provides a security warning for any mixed content. Recent changes in browsers such as Chrome, Firefox and

Read More »

Understanding DMARC

DMARC, or Domain-based Message Authentication, Reporting and Conformance, is an email authentication protocol that works alongside Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM). What

Read More »

Ready to See WhatCounts in Action?

Take your first step towards supercharged engagement!

This website stores cookies on your computer. These cookies are used to improve your website experience and provide more personalized services to you, both on this website and through other media. To find out more about the cookies we use, see our Privacy Policy. We won't track your information when you visit our site. But in order to comply with your preferences, we'll have to use just one tiny cookie so that you're not asked to make this choice again.