Skip to Content

How to Stay Healthy and Avoid the Spam Folder

If you want to stay out of the Spam Folder quarantine created by mailbox providers like Gmail, AOL, Outlook, and Yahoo, you need to know the symptoms that will get your message placed there. 


The nitty-gritty details of proprietary spam algorithms are generally kept under wraps, but we’ve done enough clinical research to be able to determine (broadly) what they’re looking at. Here’s how you can ensure your email program receives a clean bill of health.

Remedy 1: Track what people are really doing with your emails

Mailbox providers want to keep their users happy. So it shouldn’t come as a surprise that one of their key deliverability factors is what regular people do with their emails on a day-to-day basis.

Just like in real life, we’re looking for physical activity to stay healthy. Opens, forwards, replies, adding the sender email to a contact list, moving messages to (non-spam, non-trash) folders, or—probably the most important—rescuing emails from the spam folder by clicking that “Not Spam” button. The more your recipients engage with your messaging, the less likely it is that your messaging will land in spam.

If your audience is mostly interacting with your email to report it as spam or send it straight to the trash bin without so much as an open, you’re in trouble. Email providers will notice, and you’ll find yourself languishing in the spam folder along with fake Facebook friend requests, fake invitations to M A K E $ $ $ F A S T, and real fundraising messages from political campaigns.

What about unsubscribes and clicks? While these can be useful metrics to consider when you’re divining how your last newsletter performed, Gmail, AOL, Outlook, and Comcast have said they couldn’t care less.

One last element to keep in mind: increasingly, mailbox providers are personalizing deliverability. That means if I open all your organization’s emails, I’ll be far more likely to see them in my inbox, but someone less active with the same provider might see them in spam, instead.

Doctor’s Orders:

  • Try to improve interactions by running subject line and layout tests.
  • Focus on creating compelling content that encourages opens and sharing.
  • Consider occasionally asking people to reply to or forward your message.
  • Suppress people who aren’t engaging with your emails (such as anyone who hasn’t opened or clicked a message in 9 months or longer).
  • Test emails on multiple devices and in various email clients—if something looks broken, users might not interact, and could be more likely to report as spam.

Remedy 2: Avoid Spam Traps and Invalid Email Addresses

This, essentially, is how a spam trap works:

A spam trap looks like a legitimate email address, but running into one (or, more likely, many of them) can be extremely hazardous to your deliverability. A spam trap is an email address that isn’t used by a real person, and they come in two forms:

1) Recycled spam traps were once legitimate, active accounts, but they’ve since been abandoned by their owners. (Remember your first “[email protected]” account?) Mailbox providers may start using that email address as a spam trap if a user hasn’t logged in for a while.

2) Pristine spam traps were never used by a real person. They’re set up by mailbox providers solely to identify spammers. They could make it onto lists through bad recruitment practices like buying lists or scraping emails online (which you’d never consider doing, right?), but also through human error like typos, misspellings caused by transcribing a written list of emails, or people deliberately entering fake addresses (such as [email protected]—I never said all spam traps were subtle).

Either way, there’s no real person logging into these accounts to read their emails. So if you’re sending that address an email, it’s going to look pretty sketchy to mailbox providers. And if you keep sending messages to traps over and over again… scroll back up and take another look at our old friend Wile E. to see the consequences.

A related danger includes invalid email addresses: these may or may not be designed as spam traps, and they should show up as hard bounces when you send to them. Emailing a lot of invalid email addresses may also raise a red flag for email providers.

Doctor’s Orders:

  • Suppress people who aren’t engaging with your emails (such as anyone who hasn’t opened or clicked a message in 9 months or longer)—yep, we mentioned this before, and you’ll see it again!
  • Ensure your CRM is set to automatically suppress hard bounces.
  • Consider using a third-party service to validate email addresses—some can do this live on your webforms!

Remedy 3: Clean Up Your Content

When it comes to email content, mailbox providers aren’t just looking at the words in your email (although those still matter! Probably a good idea to avoid messaging about Nigerian princes or personal enhancement pharmaceuticals). They’re also looking for clean HTML in your email layout and template, and they’re checking to see if your links direct to a legit website or if those URLs are associated with spammers.

Doctor’s Orders:

  • Run code through a w3c validator like this one to check for errors.
  • Include descriptive alt text for images so they’re comprehensible and accessible even for people without images downloaded.
  • Don’t use 3rd-party, public-use link shorteners like (spammers use these to obscure links to their websites, so the link shorteners themselves have gotten a bad rep).

Remedy 4: Know Your IP Address and Domain Reputation

Your IP address is a bit like the return address on a letter—except instead of a super cute sheet of stickers you get in a DM solicitation, it’s a string of numbers that serves as the return address for your email. And just like your physical address may be either a standalone house or an apartment building, your IP address is either dedicated or shared.

A dedicated IP is yours and yours alone, giving you more control over your reputation. This is good if you’re sending a high volume of emails and want to have a firm hand on your deliverability. It’s also required for many deliverability monitoring and accreditation services.

On the other hand, a shared IP is just what it sounds like: other organizations are sending their emails using the same return address, so bad or good, you’re affected by others’ reputations. It means your organization doesn’t have as much control over or information about your IP reputation. You won’t always be able to tell if fixes you put in place are working, and a big dip in deliverability could be your fault… or someone else’s.

However, if you’ve got a small email program, a shared IP means you don’t have to worry as much about the cadence of emails or about monitoring the health of your IP address—those are things the CRM will handle.

Doctor’s Orders:

  • Ensure you have DKIM and SPF sender authentication set up correctly (this may be a good time to call in your IT department). These are essential technical keys to prove that you are the sender that you say you are.
  • Consider setting up DMARC (you’ll definitely want the IT team’s help with this!). It’s a more rigorous form of sender authentication that gives you more power to monitor and filter emails coming from your sender name.
  • If you have a dedicated IP address, monitor its reputation using a free service like to see how you’re doing over time.

When we’re talking about your email program, your domain reputation is tied to whatever comes after the @ in your email reply-to address. Just like your IP reputation, all the other factors combined contribute to how mailbox providers respond to your domain (and yes, IP and domain reputations influence each other!).

Doctor’s Orders:

  • Ensure your domain is set up to receive emails—a legit sender can also get messages back!
  • Set up postmaster@ and abuse@ email accounts, which mailbox providers will use to send complaints.
  • If you want better control over your domain reputation, consider setting up a subdomain just for your national office emails. For example, we might use instead of This both protects you from spammers stealing your online identity, and separates you from any other legit senders such as regional affiliates, volunteers, or an automated job board using your main domain.

Remedy 5: Optimize Your Sending Volume

Your sending frequency (how often you launch emails) and rate (number of emails sent per minute, as controlled by your CRM) combine to impact your deliverability and reputation.

Sending regularly is important to keep your users engaged and familiar with your content. It’s also something that mailbox providers are taking into account, particularly with dedicated IPs.

It’s also important to know that a domain or IP with no history of sending emails will be treated suspiciously by mailbox providers if it suddenly starts sending millions of emails. In instances like that, you will need to “warm up” the IP and/or domain by gradually increasing the volume of email sent from that IP/domain.

Doctor’s Orders:

  • If you’re implementing a new IP or new domain, work with your CRM to map out a plan to warm it up. This process should take several weeks and should begin with sending messages to a small list of your most active list, and scaling up from there. Plan for an overlap period when you’re sending from both the old and new at the same time.
  • Plan out your calendar in advance to ensure you have a steady stream of emails. What’s “good” will vary by email program, but in general, try not to go more than a month without sending a message, and use your common sense (and your engagement metrics!) to ensure you’re not sending too often.

If you follow our regime, you should be spam-free in no time. And if not…drink lots of water, take some Advil, and engage in a good Netflix binge. It might not fix your deliverability issues, but I know it always makes me feel better.  

View the original article here.