Get started with Postmaster Tools

You can use Postmaster Tools to track data on large volumes of emails sent and find data about your sending domain. You can view different dashboards to understand details like Gmail delivery errors, spam reports, feedback loop, and more.

To use Postmaster Tools, you need to have a Google Account. If you don’t have a Google Account, create one.

Add your domain to Postmaster Tools

  1. Sign in to Postmaster Tools.
  2. In the bottom right, click Add Add.
  3. Enter your authentication domain.
    Tip: You can add either the DKIM (DomainKeys Identified Mail) domain or the SPF (Sender Policy Framework) domain.
  4. Click Next.
  5. Verify your domain:
    • To prove that you own this domain, click Verify.
      Tip: After verification, it may take some time before your domain’s verification status updates to “Verified.” Learn more about how to verify your domain.
    • To skip this step and continue without verification, click Not now. You will need to verify your domain at some point to view any data related to that domain. To go back and verify, point to the domain you want to verify. Then, click More More and then Verify domain.

Manage your data access

If you own a verified domain, you can share your Postmaster Tools data with anyone who has a Google Account. You can also add and remove owners from your domain.

Add someone to your domain

  1. Sign in to Postmaster Tools.
  2. Point to the verified domain you want to add someone to.
  3. On the right, click More More and then Manage users.
  4. In the bottom-right, click the “Add” button.
  5. In the pop-up window, enter the Google Account email address of the person you want to access your domain's Postmaster Tools data.

Tip: When you give someone access, they won’t get a notification, so we recommend you let them know. However, they will be able to see the domain when they log in to Postmaster Tools.

Interpret numbers on the dashboard

You can use the data from the different dashboards to understand the best way for you to send your emails.

Spam rate
The spam rate is a ratio of the number of emails marked as spam by users to the number of emails that are placed in the inbox. It’s important to note that this ratio doesn’t include any email that was directly sent to your spam folder.
IP reputation

A higher IP reputation means emails sent from this IP are more likely to go to a recipient’s inbox instead of their spam folder. For example, if you send a lot of emails, and users mark them as spam, your IP reputation number will go down.

To reduce negative user feedback, you should regularly check your sending list. Be sure to only send emails to users who want your emails.

About reputations

The definitions of spam below includes mail detected as spam by Gmail’s Spam filter, and mail reported by users as Spam.

  • Bad: A history of sending a high volume of spam. Mail coming from this entity will almost always be rejected at connection time or marked as spam.
  • Low: Known to send a considerable volume of spam regularly, and mail from this sender will likely be marked as spam.
  • Medium/Fair: 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.
  • 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.


Tip: Keep in mind that spam filtering is based on thousands of signals, and IP reputation is just one of them.

Domain reputation

A higher domain reputation means emails from your sending domain (SPF and DKIM) are less likely to get filtered to a recipient’s spam folder or inbox.

About reputations

The definitions of spam below includes mail detected as spam by Gmail’s Spam filter, and mail reported by users 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.
  • Low: Known to send a considerable volume of spam regularly, and mail from this sender will likely be marked as spam.
  • Medium/Fair: 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.
  • 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.


Tip: Keep in mind that spam filtering is based on thousands of signals and domain reputation is just one of them.

Feedback loop

This dashboard is available after you set up the Gmail Spam Feedback Loop (FBL). To view a table with the identifiers flagged by FBL and their corresponding spam rates, click any data point on the graph.

About FBL graphs

  • Average FBL spam rate graph: Shows average spam rate across all identifiers flagged by FBL on a given day (when applicable) over time.
  • Identifier volume graph: Shows the number of unique identifiers flagged by FBL per day (when applicable) over time.
Authentication

This dashboard shows the percentage of your emails that passed SPF, DKIM, and DMARC over all received traffic that attempted authentication.

About SPF, DKIM & DMARC graphs

  • SPF graph: Shows percentage of mail that passed SPF vs all mail from that domain that attempted SPF. This excludes any spoofed mail. 
  • DKIM graph: Shows percentage of mail that passed DKIM vs all mail from that domain that attempted DKIM.
  • DMARC graph: Shows percentage of mail that passed DMARC alignment vs all mail received from the domain that passed either of SPF or DKIM.
Encryption

This dashboard shows what percentage of your inbound and outbound traffic is encrypted.

About TLS inbound & outbound graphs

  • TLS Inbound: Shows percentage of incoming mail (to Gmail) that passed TLS vs all mail received from that domain.
  • TLS Outbound: Shows percentage of outgoing mail (from Gmail) that was accepted over TLS vs all mail sent to that domain.
Delivery errors

This graph monitors what percentage of your total emails were rejected or temporarily failed as compared to all authenticated traffic. Under the graph, you can view a list of reasons an email failed.

About delivery errors

  • Rate limit exceeded: The Domain or IP is sending traffic at a suspiciously high rate and temporary rate limits have been put in place.
  • Suspected spam: The traffic is suspected to be spam by our systems.
  • Email content is possibly spammy: The traffic is suspected to be spammy specifically because of the content.
  • Bad or unsupported attachment: Traffic contains attachments not supported by Gmail.
  • DMARC policy of the sender domain: The sender domain has set up a DMARC rejection policy.
  • Sending IP has a low reputation: The IP reputation of the sending IP is very low.
  • Sending domain has a low reputation: The Domain reputation of the sending domain is very low.
  • IP is in one or more public RBLs: The IP is listed in one or more public Real-time Blackhole Lists (RBLs). Work with the RBL to get your IP de-listed.
  • Domain is in one or more public RBLs: The Domain is listed in one or more public Real-time Blackhole Lists. Work with the RBL to get your domain delisted.
  • Bad or missing PTR record: The sending IP is missing a PTR record.

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