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Manage Your Domain Reputation with Google Postmaster Tools

David Harris
by David Harris on April 25, 2018

Can it really be this easy?

I love details, and I love numbers. Makes sense, right? I’m a developer. Details matter because they define our work. But much as I love details, I also love simplicity. There’s an elegance to simplicity that, if done right, can make for better and more powerful solutions to complicated problems. One great example of this is Google Postmaster Tools’ reputation system. It’s surprisingly basic, and yet it works wonders in email deliverability. 

In this post, I'll explain the benefits of the system and give you a few pointers to help you get the most out of it.

When Less is More

If I were designing Google Postmaster Tools I probably would have created a detailed system that assigned a reputation score between 0 to 100—and I might have even toyed with including decimals on top of that! But not Google. They offer a simple yet powerful four-level classification, boiling everything down to an easily understood question: "How spammy is my reputation?"

Here's the not-so-secret decoder ring to their four-tier reputation system:

  • High = Rarely considered spam
  • Medium = Sends spam intermittently, along with good email
  • Low = Sends a considerable volume of spam regularly
  • Bad = High volumes of spam

 We all understand simple words like "low" or "bad.” If Google had used my method of assigning reputation in the form of numbers (like 30, 60 or 90.1573), it wouldn’t have delivered the one-two-punch email senders need when evaluating their email program. Instead, the simple answer gets them to take action! When we tell our customers and their management team, “Google considers your email reputation 'low' meaning you send a considerable volume of spam regularly," it usually makes a strong case that motivates them to change.

The Magic of Domain Name Reputation & Segmentation

You know what’s been really helpful? Like sliced-bread-level helpful? The fact that Google also makes it easy to dip into the sub-IP level of reputation. Most prior ISP reputation systems shared the reputation of an IP address, but was often too broad, especially when multiple clients (i.e. domain names) shared the same IP address. But Google Postmaster Tools can also expose this same simple reputation score on a domain-name level.

Diving into the reputation of your segments can be really powerful too. Need to look at the reputation of just part of your email stream? Here’s a tip: give that portion of email an additional DKIM signature with a unique domain name, and Google Postmaster Tools can show you the reputation of that domain name (and thus that part of your email stream).

For example, you could create subdomains based on data source:

Type of email

Signature #1

Signature #2

Data source A



Data source B



Data source C




Or based on subscriber activity/engagement:

Type of email

Signature #1

Signature #2

Subscribers less than 30 days old



Subscribers active in the last 90 days



Subscribers not active in the last 90 days




We recently helped a customer make the case to stop sending to their non-engagers by using this technique to show that the Google Postmaster domain reputation of the email sent to non-engagers was "bad," but the reputation of the recent engagers and new subscribers was "high."

GreenArrow's Special Sending Rules and X-GreenArrow-DKIM header provide the tools to set-up the multiple DKIM signatures and get this in-depth data.

Oh What a Chart Can Do

What other ISP reputation system includes a chart showing your reputation over time? None we’ve found.

Like magic, Google helps our customers see and track their email deliverability. Here’s an example of a customer who significantly improved their deliverability in just three months. (Isn’t that encouraging?) It’s easy to see how quickly things improved:


As you might expect, comparing the dates of Google Postmaster reputation changes to dates of email program changes can yield powerful insights into what caused what. For example, if you add a bunch of new subscribers and your reputation decreases from “medium” to “low,” there’s something wrong with that new subscriber list. On the other hand, if you segment out a bunch of chronically inactive subscribers and your reputation increases from “low” to “medium," you know you’ve done something right.

Common-sense correlations like these can often drive changes that will fix a declining reputation or keep things on the up and up.

Now To Convince The Rest Of The World...

As you can probably tell by now, Google Postmaster Tools has revolutionized the way we do business, both for us and our customers. And all that without getting lost in rabbit holes or number-charts. Kudos, Google!

If you’re one of the many senders out there whose reputation needs improvement, then this blog is for you. Or maybe you already get it, but you’re having a hard time telling your team, “Hey guys, we need to stop sending to this worthless, dead-end list.” In that case, show them around the tool. Or send them this blog! They just might come around.

How have you used Google Postmaster Tools? Is your deliverability improving? Seeing results in your bottom line? If you’re still stuck, we’d be happy to be a resource for you. We also sell email software to make your work easier. (But you already know that.) Until we chat again, happy sending!

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David Harris
Written by David Harris
David first started his own business when he was still in high school. DRH Internet, Inc. began as a web hosting company, but as David's consulting experience grew, he found himself working frequently with open source email servers and writing custom software to solve problems. Over time his software grew into a full-fledged email platform called—you guessed it—GreenArrrow. In his spare time, you can usually find him taking classical guitar lessons, drinking gourmet coffee, playing Go, and spending time with his wife Penni and their four amazing children.

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