Skip to main content
Google Postmaster Tools is the only way to see your spam rate and domain reputation with Gmail. Unlike other inbox providers, Gmail does not report per-user spam complaints or bounces back to email senders like OneSignal. Instead, Google Postmaster Tools provides aggregate data you can use to monitor and improve your email deliverability. Gmail is the largest inbox provider in the world, making this data essential for understanding how your emails perform.
If you send 5,000 or more emails per day to Gmail, your domain is permanently classified as a bulk sender and you must keep your spam rate below 0.3%. Postmaster Tools is the only place to monitor this for Gmail. Connect it before you reach the threshold so you have a baseline.

​
How to connect Google Postmaster Tools

1
Go to https://gmail.com/postmaster/ and click “Get Started”.
2
Input the subdomain that you have set up with OneSignal.
Google Postmaster Tools domain input showing subdomain vs root domain

mail.domain.com (subdomain) vs domain.com (root domain)

3
Click “Next” and Google will provide a TXT record for you to create in your DNS records.
  • Create this record in your DNS registrar to verify ownership of the domain.
4
Once you have created the provided TXT record in your DNS records, click “Verify”.
5
Lastly, add mailmonitor@onesignal.com as a “managed user”.
  • This gives OneSignal view-only access to help monitor your reputation on your behalf.
Google Postmaster Tools interface showing the Managed Users option

Click "Managed Users"

Adding mailmonitor@onesignal.com as a managed user in Google Postmaster Tools

Add mailmonitor@onesignal.com as a managed user

​
Monitor spam rate

This Gmail spam rate is separate from the spam metrics shown in your OneSignal dashboard. If your emails are landing in Gmail spam folders, Google Postmaster Tools may offer insight. The spam rate represents the percentage of your mail volume that Gmail recipients actively reported as spam on a given day. This data is aggregated by Google and does not identify individual recipients who reported spam. Google states: “Keep spam rates reported in Postmaster Tools below 0.10% and avoid ever reaching a spam rate of 0.30% or higher.” See Google’s Email Sender Guidelines.
Google Postmaster Tools chart showing a healthy Gmail spam rate

Gmail spam rate

The following example shows a consistently high spam rate, with peaks regularly exceeding Google’s recommended thresholds.
Google Postmaster Tools chart showing a dangerously high Gmail spam rate

Very high Gmail spam rate

Email reputation best practices

Follow these best practices to lower spam complaint rates and improve deliverability.

​
FAQ

​
Why does Google Postmaster Tools show 0% or no data for my domain?

Google Postmaster Tools requires a minimum daily email volume to Gmail before it displays data. If you’re sending low volumes, you may not see any metrics. If you do have sufficient volume, check that you added the correct domain. Data appears for the domain used in the visible “From” address header of your email, not necessarily your return-path or SMTP sending domain. Although you send from your “sending domain,” the from address in the header may be different, causing the sending domain to show 0%.
Google Postmaster Tools Authentication Dashboard showing domain details

Authentication Dashboard details from Google Postmaster for reference

​
How often is Google Postmaster Tools data updated?

Google Postmaster Tools updates data daily, typically with a 1–2 day delay. You will not see same-day data.

​
What do the domain reputation levels mean?

Google Postmaster Tools rates your domain as High, Medium, Low, or Bad based on your sending history and spam rates:
  • High: good sending history with a very low spam rate.
  • Medium: good sending history, but has occasionally generated spam.
  • Low: known to send a considerable volume of spam regularly.
  • Bad: history of sending a high volume of spam. Emails from this domain will almost always be rejected or filtered to spam.
If your reputation drops to Low or Bad, review the email reputation best practices to identify the cause. See Google’s domain reputation documentation for more details.

​
What should I do if my spam rate is above 0.10%?

Review the email reputation best practices to identify and fix the cause. Common steps include verifying your opt-in process, sunsetting unengaged recipients, and controlling send frequency.