3 Factors Determine if Email Marketing Messages Go to Inboxes or Spam

There is a lot more than words and phrases that goes into where your email marketing messages end up – inboxes or spam and junk folders. Today, email service providers (ESPs), like Google, Outlook, Yahoo, Apple Mail and so on, have elaborate algorithms that they use to determine which messages go to inboxes, which go to spam, and which are blocked entirely. It’s up to email marketers to keep up on current email marketing best practices to ensure the campaigns they send have the best chances to land in inboxes.

While ESPs’ algorithms contain thousands and thousands of data points (and they update after every email marketing campaign you send), every piece of the puzzle used to filter messages to inboxes or spam folders correlates with three primary factors: 1.) Your sending history and reputation, 2.) The content of your message, and 3.) technical settings. Let’s dive into each of these three factors so you can take the right steps to get into inboxes in the future.

Sending History and Reputation

What do email service providers think of you as a sender? If you’re sending your email marketing messages from your own domain (e.g., yourcompany.com), then you’re 100% in control of your sender reputation (also called domain reputation). 

For email marketers, it’s best to send campaigns from your own domain rather than using a shared domain provided by your email marketing platform. When you share a sending domain, you also share your sending reputation with everyone else who uses that domain, and there are a lot of spammers out there. You don’t want your email deliverability to be negatively affected by those bad actors!

LEARN MORE: Why Domain Reputation is Critical to Email Marketing and Getting in the Inbox

Therefore, if you’re sending your email marketing campaigns from your own domain, it’s up to you to build a good reputation with ESPs so they don’t flag your messages as spam. 

ESPs look at your sending history to determine if you’re taking the time to segment your lists, personalize the content you’re sending so it’s as relevant as possible to recipients, and only sending messages that people want. They determine this based on how people react to the messages you send.

In simplest terms, ESPs think you’re sending content that people want when recipients engage positively with your messages by:

  • Opening them
  • Clicking links inside the messages
  • Filing them in a folder
  • Forwarding them
  • Replying to them
  • And so on

On the other hand, ESPs think you’re not sending content that people want if recipients engage negatively with your messages by:

  • Leaving them in the inbox and never opening them
  • Deleting your messages without opening them 
  • Waiting a long time to open them
  • Marking them as spam 
  • Blocking you as a sender
  • And so on 

As an email marketer, it’s up to you to invest the time and effort into building and maintaining a good sending history and reputation. 

Here are some of the things that matter most to showing ESPs you’re a good sender so your messages make it to recipients’ inboxes rather than their spam or junk folders:

  • Send on a consistent schedule
  • Don’t send to more than double the number of recipients that you sent your last campaign to
  • Don’t send duplicate content that you’ve already sent in a previous campaign
  • Segment your lists and personalize the content in your message so it’s as relevant as possible to the specific people on each list
  • Clean your lists and remove people who are unengaged

If you follow the above best practices, you’ll be on your way to developing a good sender reputation and getting your messages into inboxes. 

LEARN MORE: Why You Must Clean Your Email Marketing List to Get the Best Results


The second factor that email service providers use to decide if your email marketing messages get delivered to inboxes is the content inside of your messages. The first thing to consider when writing email marketing messages is relevancy because people are unlikely to positively engage with messages that aren’t highly relevant to them. 

How do you ensure you’re only sending highly relevant messages? You segment your lists into laser-focused audiences and send hyper-relevant content that is personalized to each unique audience. One-size-fits-all doesn’t work in email marketing anymore. 

In fact, the spray-and-pray approach is a ticket to the spam folder today because generic messages sent to bulk lists don’t get enough positive engagement – they’re not relevant to enough recipients. As a result, you’ll get more negative engagement, which hurts your sender reputation and the deliverability of all of your email messages in the future. 

Instead, create buyer personas and customize your message content for each persona to get the most engagement and the best results. Yes, it’s easier to send one message to everyone and hope someone bites. However, sending that one message can do a lot more harm today than good because ESPs could mistake you for a spammer.

LEARN MORE: How to Create B2B Buyer Personas to Improve Email Marketing Results

In addition to prioritizing segmentation and personalization to improve relevancy and boost engagement, you also need to be aware of current spam triggers that ESPs algorithms look for. 

Keep in mind, if your sender reputation is high, then you can probably get away with having some common spam triggers in your messages and still make it to inboxes. However, if your sender reputation isn’t high, then just one spam trigger could be the difference between getting to inboxes or landing in spam. 

Here are some common spam triggers to avoid:

  • More images in your message than text
  • Excessive number of links in your message
  • Hard to see unsubscribe link
  • No clear and obvious physical mailing address for the sender
  • Excessive capitalization, punctuation, or special characters in the subject line
  • Poorly formatted HTML
  • URL shorteners
  • Embedded forms, embedded videos, Flash, or Javascript
  • Excessive spelling or grammar mistakes
  • Hidden text

Remember, ESPs’ spam algorithms include thousands of criteria, so the above list is far from complete. However, these are some of the most common spam triggers that you should definitely avoid if you want to have a chance to make it into inboxes.

LEARN MORE: 10 Reasons Your Email Marketing Messages Don’t Get to Your Recipients


Email service providers use a variety of technical settings to ensure senders are who they say they are. To get the best deliverability, you should send your email marketing messages from your own domain and make sure all of the necessary tech settings are set up correctly. 

Here are some of the technical things you can set up to prove who you are to ESPs and help deliverability:

  • DNS (Domain Name System): Your email address is matched to your domain name, and a DNS text record is used to match it to a sending IP address.
  • SPF (Sender Policy Framework): This text file shows email clients the IP addresses that are allowed to send mail on behalf of your domain.
  • DKIM (DomainKeys Identified Mail): This is a text file that shows messages aren't altered in between the sending and recipient servers.
  • CNAME (Canonical Name): This is a text record that connects an alias name to a true name (for example, www.yourcompany.com and yourcompany.com).
  • DMARC (Domain-based Message Authentication, Reporting and Conformance): This is a policy that tells email clients messages are protected by SPF and/or DKIM.
  • Sender Information: Your sender domain (e.g., yourcompany.com) should match your sender email address (e.g., john@yourcompany.com).

Don’t feel overwhelmed by all of those acronyms! Configuring the technical settings is usually something you can work with your email marketing platform provider to accomplish. For example, if you subscribe to the Cannabiz Media License Database to send email marketing messages to hemp and cannabis license holders, you can work with the Cannabiz Media team to ensure all of the technical pieces are set up properly.

Key Takeaways about Getting Your Email Marketing Messages into Inboxes Rather Than Spam

Email deliverability is a big topic, and this article just brushes the surface. However, every little thing you do to show ESPs you’re a good sender helps! Work on building and maintaining a positive sender history and reputation, segment your lists, personalize your message content, avoid common spam triggers, and get all of your technical settings configured. It won’t take long for you to see better results from your email marketing investments.

Discuss On Twitter