Definition
Google Postmaster Tools gives senders direct insight into how Gmail treats their mail. It shows aggregate data on delivery errors, IP and domain reputation, spam complaint rates, authentication results, and feedback loop statistics. It is the single most important tool for any sender whose audience includes Gmail recipients.
Key Metrics
- IP reputation: How Gmail rates your sending IPs (bad, low, medium, high)
- Domain reputation: Your sending domain's reputation with Gmail
- Spam rate: Percentage of your mail marked as spam by Gmail users
- Feedback loop: Complaints reported by Gmail users who hit the spam button
- Delivery errors: Temporary and permanent delivery failures
- Authentication: SPF, DKIM, and DMARC pass rates
Setup
Sign up at postmaster.google.com and verify your sending domain by adding a DNS TXT record. Data takes a few days to appear after verification. You need a minimum sending volume (typically 200+ messages per day to Gmail) to see data.
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