Google Postmaster Tools is a free service that shows how Gmail sees your sending domain: spam rate, domain and IP reputation, authentication results and delivery errors. You verify domain ownership with a DNS record. Data appears only when you send enough mail to Gmail users each day.
How do you set it up?
- Sign in to Google Postmaster Tools with a Google account.
- Add your sending domain.
- Google gives you a TXT record. Add it to your domain's DNS.
- Return to Postmaster Tools and verify.
- Wait for data. Give it a few days of normal sending.
Verify the domain you use in the visible From address, and consider adding subdomains you send from.
What do the reports show?
- Spam rate. The share of mail that Gmail users marked as spam. Google asks bulk senders to stay below 0.30% and recommends under 0.10%.
- Domain and IP reputation. Gmail's rating from bad to high.
- Authentication. The percent of mail passing SPF, DKIM and DMARC.
- Encryption. The percent sent over TLS.
- Delivery errors. Rejections and temporary failures, with reasons.
Postmaster Tools has been updated over time, so dashboard names and layout may differ from this description.
Why is my dashboard empty?
Common reasons are low volume, a domain that has not been verified or a new setup. Postmaster Tools reports aggregate data and hides it when volume is too small to be meaningful. If you send little to Gmail, use seed tests and platform reports instead.
How should you act on the data?
A spam rate that rises means something about the audience or content changed. Check consent, frequency and segments. A failing authentication chart means a sender is not set up properly, so use the authentication guide. A reputation drop calls for the repair steps. These numbers also show whether you meet the bulk sender requirements.
Which domain should you add?
Add the domain that appears in your visible From address, since Gmail evaluates mail against it. If you send from several subdomains, such as one for marketing and one for receipts, add each so you can compare them. A problem on one stream then shows up without being averaged away by the others.
What other free tools complement it?
Microsoft offers Smart Network Data Services for Outlook.com IPs. Use blocklist lookups as covered in the blocklist guide. For paid options, compare email deliverability tools. The overall view is in email deliverability explained.
Frequently asked questions
Is Google Postmaster Tools free?
Yes. It is a free service from Google.
Does it show data for all my email?
Only mail delivered to Gmail and Google Workspace-style personal accounts at sufficient volume. It does not report on other providers.
How often does the data update?
Data is reported per day, and may lag. Check the dashboard for the latest date shown.
Do I need Postmaster Tools if I use an email platform?
It is still useful, because it gives you Gmail's own view, independent of your platform's reports.