Email Sender Score

Updated June 19, 2020

Are your marketing emails or email newsletters finding their way into an inordinate number of recipients' spam folders? Can't figure out why?

Have you checked the reputation of your company's domain name? Didn't even know that was a thing?

It is.

What Is Email Reputation?

Your email address has a reputation that can either keep messages from landing into inboxes or help it sail on through all the algorithmic filters that prevent us from drowning in a deluge of unwanted and unsolicited email.

There are many factors that can contribute to your domain name's reputation, either negatively or positively.

Think of how people respond to the commercial emails they receive, and you'll get an idea of the types of user behavior that can contribute to damaging the reputation of your domain name.

Email User Behavior

Obviously, if you send emails to people who have not consented to receive emails from you, they will likely react negatively by clicking on the spam button in their inbox or unsubscribing and listing the reason they've unsubscribed as spam.

This is monitored by both email marketing service providers like MailChimp or ExactTarget as well as at the individual level by email service providers like Gmail.

Another factor that can contribute to your domain name's email reputation is the activity, or lack thereof, of your email list subscribers.

Do your emails routinely get very small open rates? Are they often deleted without being opened? That's a signal to email service providers that the quality of your emails may be poor, and perhaps unsolicited.

Content Of Your Email

If your email communications look like spam, it'll probably be treated like spam by both recipients and spam filters alike.

A good way to check to see if your emails look "spammy" is to study your own junk folder.

What kinds of emails end up there? What do they look like? What language do they use in the subject line and the body of the email?

Does your email use one large image as the content of the missive? That is a common trick of spammers.

Do you use massive font sizes? Are they red? These, too, are common elements of spam emails.

Look for false-positives as well, that is, emails you want to receive but have somehow ended up in your spam folder. Can you see a pattern that would indicate why those emails got filtered?


If enough signals are generated that reflect spammy behavior from your email address, it is possible your domain will get listed on an email blacklisting service.

Blacklisting services host lists of known spammers that email filters consult in order to efficiently block out emails from known spammers.

Obviously, you want to avoid this.


Whitelists, conversely, are a way for email addresses to more easily bypass spam filters.

That is why you often get instructions on how to add an email address to your contacts or request to ask your system administrator to add an address to their whitelist after you subscribe to a newsletter.

7 Email Sender Reputation Tools

So how do you figure out your email address' reputation? Here are five tools that help you do just that.

1. Sender Score

One tool you can use to get started is Sender Score by Return Path.

Sender Score measures your domain name or IP address in terms of email reputation. Just go to the site and create a free account.

Once you've created an account, enter your domain name or the IP address from which you send email and view your report.

Scores are calculated from 0 to 100. The higher your score, the better your reputation. The better your reputation, the higher your email deliverability rate is likely to be.

2. Sender Base

Senderbase is a product of Cisco and provides you with the tools to check your reputation by ranking you as Good, Neutral, or Poor.

  • Good means there is little or no threat activity.
  • Neutral means your IP address or domain is within acceptable parameters, but may still be filtered or blocked.
  • Poor means there is a problematic level of threat activity and you are likely to be filtered or blocked.

3. Reptuation Authority

WatchGuard's ReputationAuthority helps protect business and government organizations from unwanted email and web traffic that contain spam, malware, spyware, malicious code, and phishing attacks.

You can look up your IP address or domain, receive a reputation score from 0-100, and get the percentage of emails that were good versus bad.

4. Barracuda Central

Barracuda Networks provides both an IP and domain reputation lookup via their Barracuda Reputation System; a real-time database of IP addresses with "poor" or "good" reputations.

5. Check TLS

The Check TLS tool will check your email encryption. TLS, or Transport Layer Security, is a "cryptographic protocols designed to provide communications security over a computer network. Several versions of the protocols find widespread use in applications such as web browsing, email, instant messaging, and voice over IP," according to Wikipedia.

You can use this tool to get a TLS Confidence Factor for your sending domain.

6. Spamhaus

Spamhaus maintains a database of IP addresses and domain names that have been blocked by Internet Service Providers for spaming behavior. You can check to see if you have been put on a blacklist using Spamhaus' lookup tool. Just enter the IP address of your sending domain or the domain itself.

7. Gmail Postmaster Tools

Google provides a service specifically for its Gmail service. Gmail Postmaster Tools provides access to analytics and diagnostics to try and determine why your emails may be getting trapped by Gmail's notoriously strict spam filters.