How to Check Your Domain Reputation with Google Postmaster Tools

google postmaster domain reputation

How to Check Your Domain Reputation with Google Postmaster Tools

Google Postmaster Tools(GPT) is a free service from Google that provides email senders with insights and analytics their email processing and deliverability. Utilizing Google Postmaster Tools, domain owners can retrieve data in aggregate regarding spam complaint rates, IP reputation, domain reputation, feedback loops, delivery errors, authentication, and transit encryption.

Google Postmaster Tools helps answer the questions like “What is my IP reputation at Google?”. While Google provides helpful documentation, they leave some ambiguity that we can help clear up.  In this blog we are going to cover what the Google Postmasters Tools are, how you get access, how you can use them, and other questions that don’t specifically get answered elsewhere.

What Are Google Postmaster Tools?

Google Postmaster Tools is a completely free set of email analytics tools that allow domain owners to monitor important factors associated with their email performance through Gmail. The tools give senders insight into important metrics that can help identify problem areas in their email sending practices and fix these areas to improve overall success rate and deliverability. Once the sender sets up their account and verifies their domain, they have free access to the following information:

  • Domain Reputation
  • IP reputation
  • Spam Rate
  • Feedback Loop
  • Authentication
  • Encryption
  • Delivery Errors

There are a few caveats to understand regarding all these datapoints and metrics. First is that Google Postmaster Tools only reports on messages that they successfully associate to a domain via either SPF or DKIM authentication.  Organizations that do not properly authenticate their mail with their own domain are not able to access this data.

Next, is there a certain minimum daily email volume threshold for data to populate in the Google Postmaster Tools.  This means very small senders may not have data appear in their reporting dashboard. Google doesn’t publish the specific threshold, but we’ve found our customers sending more than 100 messages per day to unique Gmail users will reliably have reputation data generate for the day. Reports generated by Google update once per day providing insights into the prior day’s performance.

This brings us to our final caveat, which comes back to a question we get all of the time – How often do Google Postmaster Tools get updated?”  Data is only provided in aggregate and on a per day basis. This leaves lots of ambiguity to the data that they provide, for example – rather than give you a score of 0-100, Google will bucket IPs and Domains into groups such as “High” or “Medium” performance tiers.  Let’s first learn how to get access to your data and then break down the tiers you may encounter!

Getting Access To Google Postmaster Tools

The process of using Google Postmaster Tools all starts with having a Google account and validating your ownership of sending domain(s).  The first step is to visit the website for Google Postmaster Tools and sign-in to your Google Account.

Once signed-in, if you haven’t verified ownership of any domains previously, you’ll be asked to add your first domain –

set up google postmaster tools

If you already have a domain verified, you can add additional domains using the red plus icon in the lower right-hand corner of the page.

setup google postmaster tools

Once you’ve entered your first domain, Google will provide you with the unique DNS record that you will need to create to verify ownership.  The primary verification method that Google presents is a DNS TXT record.  They also indicate a secondary verification method of CNAME record. Due to the general bloat of DNS TXT records, SocketLabs recommends that everyone uses the DNS CNAME verification method.

setup google postmaster tools

It may take some time before Google can verify the DNS record.  You’ll see the domain in your management list, but access to the data is not provided until the DNS records are verified.

postmaster tools setup

You see the domain status flip to “Verified” once the DNS records have been properly published.

google postmaster tools setup guide

It is critical that you DO NOT delete the DNS records once it is verified.  Google will re-verify the DNS record exists every 30 days.  If verification fails, access to the data for the domain is removed from the Google account.

Sharing Access Within your Organization and with SocketLabs

Once you’ve verified ownership of your domain, you can manage and delegate access to Google Postmaster Tools to others.  Providing access to all necessary stake holders is essential to ensure the data is properly being monitored.  To start sharing access with others you can follow these steps

  • Sign-in to Gmail Postmaster Tools –
  • Hover your cursor over the domain for which you want to share access
  • On the right side of the list item, click the “⋮” options menu and click “Manage Users”google postmaster tools access
  • Additional users can be added by clicking the red “+” button in the lower right-hand corner of the screen
  • In the pop-up wizard, add the email address of the user you’d like to have access. For SocketLabs customers sharing access with SocketLabs the following address should be added [ [email protected] ]

SocketLabs is excited to be building an integration directly with Google Postmaster Tools that will require you to share access for the functionality to work.  Sharing access with SocketLabs also helps our team of email experts provide help if you encounter delivery issues to Gmail, and help monitor your service performance.  Now that you are set up, lets look into what that reputation tiers are like once you’re in.

The Reputation Tiers

Now that you have access to Postmaster Tools, the first thing that we recommend you dive into is the IP and Domain reputation insights.  When providing reputation data, Google Postmaster Tools categorizes domains and IPs into one of four buckets – High, Medium, Low, and Bad. Google defines each in their documentation as:

High: Has a good track record of a very low spam rate, and complies with Gmail’s sender guidelines. Mail will rarely be marked by the spam filter.

Medium: Known to send good mail, but has occasionally sent a low volume of spam. Most of the email from this entity will have a fair deliverability rate, except when there’s a notable increase in spam levels.

Low: Known to send a considerable volume of spam regularly, and mail from this sender will likely be marked as spam.

Bad: A history of sending an enormously high volume of spam. Mail coming from this entity will almost always be rejected at SMTP or marked as spam.

One little known secret about these buckets that we can share from our experience with these tools is that the buckets once had different names. During its beta testing phase, Google Postmaster Tools used the following bucket names:

Beautiful (now High)

Good (now Medium)

Bad (now Low)

Ugly (now Bad)

You can actually still see a trace of this in the URL query string parameters within GPT.

We’ve found that knowing the original bucket names helps senders be more accepting of their “Medium” categorization, as this is a bucket many marketers find themselves in.  This also helps us here at SocketLabs in forming our recommendations to our customers.  We suggest that they maintain High or Medium reputations for their domains and dedicated IPs to ensure reliable inbox placement rates.

For research we conducted and presented during our Summer of 2020 deliverability webinar series, we found drastic performance differences in the reputation buckets, especially at the top and bottom buckets.  The following slide excerpt shows the average unique Gmail open rate for customers sending on a dedicated IP address in the corresponding reputation bucket.

I think the biggest take-away here is that Bad reputation IP addresses don’t reach the inbox at all, and that the Low and Medium reputation buckets can still reach the inbox, but with obviously decreasing rates of success.  Since our analysis only looked at IP reputation, it is very likely the other factors like Domain reputation influenced the success for messages sent by the IPs in these buckets.  This is why low IP reputation senders are able to still achieve unique open rates at ~17%

Now that we have a full understanding of these reputation buckets let’s take a look at how the tool presents this data and what other things you need to know about each data point.

Domain Reputation

postmaster domain reputationThe most heavily weighted metric by the Gmail spam filters when determining inbox vs. junk folder message placement is domain reputation.  So, it is no surprise that this metric is the most frequently asked about of all the data points provided by Google.  For many senders, especially those using shared IPs for the delivery of their messages, there is a reliance on their domain reputation to ensure successful delivery of messages.  This make it one of the most important metrics to monitor.

We find that performance begins to significantly tail off at the Low or Bad reputation tiers.  Senders with domains in these tiers will want to look at their email practices and adjust accordingly.  It is important to note that the domain reputation in Google Postmaster is only for the domain that was configured in the set-up process, and it is derived from an analysis of all authenticated messages sent to Gmail.  If a single given domain sends multiple streams of authenticated messages – transactional, marketing, and personal then this domain reputation will be an aggregate of performance across all of these streams.  This includes mail sent across different vendors or platforms, assuming messages are using SPF or DKIM authentication.

While Google presents this data on a day-to-day basis, we find that the actual calculation is based on a trailing period of time.  Messages sent weeks or months ago may still be impacting the reputation Google calculates for you today. We believe the reputation of prior days slowly trails off in terms of its weight, with most recent messages bearing the most weight.  Ultimately this stabilizes the data and prevents drastic increases or decreases. This also means that changes to sending practices may take significant time to be realized in the data displayed in Google Postmaster Tools.

For a more finite analysis, you can also add sub-domains to Google Postmaster Tools. Once you’ve verified ownership of an organizational domain, all sub-domains can be added and are instantly verified without any additional DNS records being created.  The reputation of all sub-domains will always automatically bleed/aggregate up to the organizational domain, but you can monitor performance on individual sub-domains as well.  Keep in mind, the sub-domain must be used in the authentication of messages in order for a reputation to be calculated.  For example, SocketLabs customers can add their Custom Bounce Domain to GPT to calculate SocketLabs specific domain reputation performance.

IP Reputation

IP reputation, like domain reputation will help provide insights regarding the success of your messages. The higher your reputation, the more mail is landing in Gmail inboxes. It is important for senders that are monitoring this metric to understand if the IP addresses listed in GPT are dedicated or shared IP addresses.  Dedicated IP addresses obviously more accurately and directly reflect performance.  The reputation of Shared IP addresses may not be a direct reflection of the performance of a sender.  It is still important to monitor though as it may indicate potential performance issues caused by those the IP address is shared with on the given service.  Over 97% of shared IP addresses operated by SocketLabs maintain a “High” postmaster reputation at Google.  We closely monitor and manage the performance of our shared IP addresses to ensure excellent performance for all customers.

postmaster ip reputation

One of the drawbacks to the IP reputation insights offered by Google are the means in which they visualize the data for users.  For each day, Google presents a bar that represents the count of how many IP addresses fall into each category.  This can be extremely misleading as an organization that sends mail across 2 IP addresses where one that sends 10 million messages per day with a bad reputation and one that sends 5 thousand messages per day with a good reputation, each will be weighted equally with 50% of the graph.  Beyond the lack of volume being incorporated to the visual representation, it is nearly impossible to track a single IP address over time in the visualization presented by Google.

User Reported Spam Rate

The User Reported Spam Rate page in Google Postmaster Tools helps senders identify the rate at which their messages are being marked as spam by recipients.  Unlike most other large mailbox providers, Google does not offer a recipient specific feedback loop service.  This means that data about individual users that click spam is not available.  They only provide this data as an aggregate rate.  This metric is essentially equivalent to the compliant rate generated by SocketLabs in your Control Panel.  We recommend senders keep their User Reported Spam Rates at 0.0% or 0.1%.

postmaster spam rate

Because the reporting is so high level, you will not get too much additional information on your email other than X% of your total messages are being moved from inbox to the spam folder by recipients. Most SocketLabs customers achieve a 0.03% compliant rate or below, and since Google only displays this data in increments of 0.X% – this value will be rounded down and reported at 0.0% for most good senders.

This also means that there really isn’t much value that can be derived from this report by Google.  Some good senders may see spikes in this data, but we’ve often found they’ve correlated to send volume decreases.  Since complaints are asynchronous events, if you send a large campaign (100k+) on a Tuesday, but only send a hundred messages on Wednesday, a handful of complaints from Tuesday’s campaign that are initiated by users on Wednesday could drive your User Report Spam Rate on to be confusingly high on Wednesday.  For consistent large volume senders this metric should remain fairly consistent.

Feedback Loop

The Google Postmaster Tools Feedback Loop is the only feature offered by Google that pre-dates the launch of the postmaster tools. Originally launched in 2014 as a mechanism for high volume senders like SocketLabs launched for ESPs

The feedback loop information is going to provide a little more detail about where your complaints are coming from based on an identifier in the message header.  Once you get a certain amount of feedback loops, Google will start automatically putting your messages in the spam folder.  You can however avoid this reaction if you are continuously monitoring and resolving issues that are causing these feedback loops.

postmaster feedback loop

Delivery Errors

Google Postmaster helps identify delivery errors that are happening with emails sent to a Gmail account.  The cause of the delivery error is typically noted in the dashboard and can include malicious attachments, DMARC policy issues, suspected spammy content, rate limit exceeded, etc.  The delivery errors area will not tell you if you are outright blocked due to reputation errors because those messages are heading straight to the junk folder and Google will only provide reporting based on emails going to the inbox as previously mentioned.

postmaster delivery error


In the encryption dashboard you can see the rate of success in using TLS encryption.  If you send through SocketLabs for example, you will see 100% encryption because we honor Google’s encryption policies and enforce TLS.

postmaster encryptionAuthentication

The authentication dashboard shows you the rate of your mail that is being authenticated.  The only mail that will display in the authenticated traffic log will need to have passed SPF or DKIM.  Unfortunately, this skews the data slightly because you won’t see unauthenticated mail.

postmaster authentication


Does Google Postmaster have an API?

Yes, Google recently announced that there is a Postmaster API that allows users programmatic access to important metrics on their email sending efforts including all of the areas mentioned above: IP reputation, domain reputation, spam, errors, feedback loop, authentication, and encryption. Here at SocketLabs we have implemented some basic tools around this API for robust internal monitoring and reporting tools and we look forwarding to bring the data and insights to customers directly in the SocketLabs Control Panel.

Using Google Postmaster Tools to Improve Your Email Deliverability

Using Google Postmaster tools helps senders better understand their email efforts with high-level reporting on important metrics.  Whether you’re looking for how to check your domain reputation or trying keep an eye on your encryption and authentication, Google Postmaster Tools help all high-volume senders get more insight into their email.  And the best part is it’s free.