ActiveCampaign's deliverability guide to Gmail


Gmail is the top email provider of both B2B and consumer mailboxes in the US. Google operates and also provides Google Workspace for businesses. Workspace email addresses follow similar deliverability rules as any ordinary consumer Gmail address.

This article will guide you through best practices from Gmail and ActiveCampaign that will help you achieve success with Gmail. 

Bulk sender guidelines

Gmail has a fantastic guide called "Prevent mail to Gmail users from being blocked or sent to spam." This is one of the best places to learn about best practices and good deliverability with Gmail. 

This guide, along with this article, lays out the fundamental tenets you'll need to focus on for great deliverability with Gmail.

Domain vs. IP reputation

Your domain reputation is the most important factor for delivery at Gmail. It's even more important than your IP reputation. Gmail has a very sophisticated, intelligent machine-learning model that tracks the activity of every domain. The history of your domain reputation is what will determine your delivery to Gmail.

Because domains carry such special weight at Gmail, you should try to use as few domains as possible. This will help you keep a static, condensed reputation. You should also avoid using a new domain if you can. A new domain will have sub-par deliverability at Gmail for at least a few weeks as it builds a positive reputation.

You should only switch out your domain if you absolutely have to. If you do switch out your domain, be aware it will take some time for the new domain to warm up.

In this article, when we refer to “sender reputation” we are referring to your overall domain reputation.

Why engagement is important for Gmail deliverability

Engagement is the bedrock of deliverability to Gmail. You should focus on engagement above all else.

Gmail says in its guide, “Send mail only to users who choose to get and read your messages.” This means you need to send messages to recipients who have opted into your list and have positive interactions with your emails. Doing so will help you establish a rock-solid domain reputation and avoid deliverability issues.

These are examples of positive interactions a user can have with your messages:

  • Opening
  • Forwarding
  • Replying
  • Marking as not spam/dragging from spam folder to inbox
  • Dragging a message to the primary inbox
  • Starring/Marking as Important

These are examples of negative interactions a user can have with your messages:

  • Marking as spam
  • Not reading, or deleting without reading
  • Marking as phishing

Users marking a message as spam, or spam complaints, is a very negative signal that directly impacts your domain reputation. It is best practice to keep your Google Spam Rate below 0.1%. Anything above that value is considered potential spam, and anything above 0.3% will be filtered as spam immediately. We recommend setting up Google Postmaster Tools to give you visibility over your Spam Rate.

Beyond this, Gmail has hundreds of sensors that determine domain reputation. Anything you've sent to Gmail will be analyzed and contribute to your sending reputation. 

It's important to keep a clean list of engaged contacts who open at the highest rate and have positive interactions with your emails. This is known as "list hygiene."

The worst thing you can do for your sender reputation at Gmail is send mail to lists of contacts who don’t open your messages. If you routinely send to old lists of unengaged users at Gmail — even if these users did opt-in and were engaged at one point — your domain reputation will crumble. Gmail will consider the mail unwanted and sort it in spam.

If a contact is not opening your messages, you should send to them less often and “confirm users want to stay subscribed,” as Gmail says. After a certain amount of time, you should not send to them at all, or as Gmail puts it, “Consider unsubscribing users who don’t read your messages.”

This “sunsetting” time frame depends on your business, but we recommend you stop sending emails to anyone who hasn’t opened in 12 months. Ideally, you should use a shorter sunset period. Some brands may even choose to sunset subscribers after as little as 30-60 days of not opening. This tactic usually yields spectacular delivery to Gmail.

Resources on keeping an engaged list

Success Hours: Email Engagement and Deliverability

Why Email Engagement is the Holy Grail of Email Deliverability

Personalized delivery

Gmail uses engagement to determine inbox placement for each recipient. For example, your email may go to the inbox of one recipient and spam to another. This is based on each unique recipient’s preferences of what they typically read and don’t read.

It's important to remember if you have someone reach out and say they received messages in spam at Gmail. It's possible this only happened to them. A good way to test this is to open a new Gmail account and send a message there. If you see it in the inbox, you are in good shape. If that test goes to spam, you likely have a real problem.

We also recommend setting up Google Postmaster Tools. Doing so will give you an objective aggregate of your sender reputation at Gmail and not be biased by what happens with one particular recipient. It will also give you visibility over your Spam Ratee so that you can keep that metric under control.


  DKIM and DMARC authentication is required beginning February 2024 following upcoming changes by Gmail and Yahoo regarding authentication requirements. ActiveCampaign highly recommends all senders set up DKIM and DMARC. Learn how to set up DKIM and DMARC authentication.

For more information on these changes see our blog post A Guide to Google and Yahoo authentication Changes in 2024.

Not only is DKIM authentication vital for Gmail, it will also remove the “via” header you may see in Gmail:


Read the "How do I remove the 'Sent on behalf of header" help article for more information on this topic.

Gmail also requires that you set up a basic DMARC record. DMARC is something you need to set up yourself. You can follow our "SPF, DKIM, and DMARC authentication" help article to learn how to set it up. Please make sure you have your own DKIM in place before implementing DMARC. If you already have a DMARC in place, you do not have to change it.


Domain reputation is very important at Gmail. To further solidify your domain reputation with Gmail, you can set up a custom domain and a custom mail server domain if your current plan allows it. This will ensure your domain is used throughout your messages instead of ActiveCampaign shared domains.

Increase sending volume at a slow pace

When starting with ActiveCampaign, you must warm up your IP at a slow pace. Gmail considers sending spikes without an adequate warmup as spammy. When Gmail detects spammy behavior, it will throttle your messages, and your sender reputation will suffer.  Our shared IP addresses are very warm, but you still need to ease into sending with them if you are a high-volume sender. This will help to warm up the domain reputation on these IPs.

Send mail at a consistent rate. Avoid sending mail in bursts.

It's important to avoid any drastic spikes in sending. For example, let's say you have a large monthly newsletter list. Instead of sending to the entire list all at once each month, you should break the list into smaller segments, and send the email over several days to each segment. Anything you can do to keep the sending volume more consistent and less “spikes” the better.

As a rule of thumb, this “spike” in sending volume is especially dangerous if it's too abrupt. If you are going to jump from 10,000 to a busy day of sending 20,000, you might be fine. But if you typically send 25,000 and you plan on sending 100,000 on a busy day, that's something you should avoid.

Learn how to warm up using shared ActiveCampaign IPs.

Learn how to warm up a dedicated IP.

What to avoid

  • Don’t send sample phishing messages
    You also should avoid mismatching any URLs in your messages. Mismatched URLs can make your email messages look like a phishing attempt. For example, if you have a plain URL in your message that purports to direct to, it should be hyperlinked to, not somewhere else.
  • Make sure users opt-in to get mail from you
    This means you shouldn’t send messages to a user about a brand they didn’t explicitly opt in to. This also means that all forms of list purchasing, list appending, list scraping, and list trading/brokering should be avoided, as they are sure to tank your deliverability at Gmail
  • Avoid opt-in forms that are checked by default and that automatically subscribe users
    You should obtain express opt-in from your subscription forms. You should not pre-check the opt-in box or include fine print about sending marketing messages. You should only message contacts if they have expressly opted into the brand you are sending for.
  • Be careful with affiliate marketing
    Gmail is very wary about affiliate marketing as spammers often take advantage of affiliate marketing programs. If your brand is associated with marketing spam, your other emails may also be marked as spam. Any affiliate links you use must be embedded within the context of a real, valuable brand and engaging content. If you are blasting out offers simply to get clicks on affiliate links, your deliverability will quickly decline at Gmail.
  • Make sure your domain isn’t listed as "Unsafe" with Google Safe Browsing

What about the Gmail Promotions tab?

The Gmail Promotions Tab is the inbox. Studies show that the promotions tab has no negative effect on open rates and engagement with your messages.

Messages in the Promotions tab are read at a healthy, normal rate. Some industries even see higher conversion rates with messages in the Promotions tab because it's a helpful way for end-users to categorize marketing messages. Importantly, there is no shortcut or way to trick Gmail into avoiding the Promotions Tab even if you wanted to.

Read the "Hype and truth about Gmail tabs" help article for more information on this topic.

Other tips for good deliverability with Gmail

Here are some other tips that can help ensure good deliverability with Gmail:

  • Use Postmaster Tools to monitor your domain reputation
  • Confirm each recipient's email address before subscribing them to your list
    This can be done with a double opt-in form. If possible, we also recommend using a captcha to stop bots from filling out your forms.
  • Make sure your unsubscribe links are prominent and easy to find  
    It's better to have contacts unsubscribe from your emails than to have them mark emails as spam or become zombie subscribers who never open and degrade your sender reputation.
  • Use a consistent "From" email address as much as possible
    And ask users to add it to their contact list. Gmail says, “Messages that have a From address in the recipient’s Contacts list are less likely to be marked as spam.”

Technical Requirements

ActiveCampaign has the technical requirements set up that the Bulk Sender Guidelines mention:

  • TLS is enabled on all outgoing messages
  • Reverse DNS is set up for all ActiveCampaign IP addresses
  • One-click list-unsubscribe headers
  • A valid message-id header is included for you (RFC 5322)
  • Messages are formatted according to Internet Format Standard (RFC 5322)
  • We maintain accurate WHOIS information for our shared mail domains
  • ActiveCampaign "Provide[s] an email address for message recipients to report email abuse.” The email address,, will be in the headers of all messages.
  • The ActiveCampaign deliverability team “Monitors shared IP address reputation” to ensure you're not on any blocklists

Warnings about phishing

When sending to Gmail, you may run across a warning like this:


This happens if the domain in the "To" and "From" email addresses are the same, but the "Reply to" email address uses a different domain. Learn how to troubleshoot this phishing warning.

Warnings about spam

You also might see warnings like this in Gmail:


If you see a warning like this, it does not mean there is a technical problem. This means your domain or your content has acquired a negative reputation on Gmail. We recommend signing up for Google Postmaster Tools to get more insight. Then go through the various best practices we outline in this guide to try and improve your sending reputation.

If your domain has acquired a negative sending reputation do not swap it out for a new domain. Gmail’s sophisticated systems can easily identify this type of activity. This will only result in making the problem worse for both the new and old domains.

Avoid focusing on technical problems

It's tempting to spend a lot of time hunting down technical problems when you believe you have a deliverability issue at Gmail. Sometimes there can be a technical problem, but it's rare. Most of the time, a delivery problem at Gmail is because best practices were violated.  Often the list contains unengaged, old, not properly opted-in contacts, or the content is not what people signed up to receive. If you have problems with Gmail, it's best to focus on list hygiene and best engagement practices, instead of technicalities. We’ve found that if you have a good, clean, engaged list of contacts, you will have no delivery problems at Gmail.

Contacting Gmail for Help

Gmail does have a form you can use to contact them. This form is intended for acute technical issues; it will not help if you have issues with messages going to spam. If your messages are going to spam, you should follow the tips above to improve the engagement of your list so that you can remediate your sender reputation at Gmail.

Additional Resources

We’d like to credit:

Much of what we said here comes from their insight. These resources help you learn more about the nuances of deliverability to Gmail and deliverability in general.

Was this article helpful?
5 out of 7 found this helpful

Have more questions? Submit a request

Start free trial