Google Postmaster Tools: a complete walkthrough
Setting up Postmaster Tools, reading every dashboard, and turning the eight metrics into concrete deliverability fixes.
Google Postmaster Tools is the closest thing to a reputation dashboard the email world offers. It's free, it's the canonical source for how Gmail sees you, and it's the first place to look when placement degrades. If you send any volume to Gmail, you should be reading PMT every Monday.
Setup in three steps
Postmaster Tools enrollment
- 01
Add the TXT record
In PMT, click "Add domain." Google generates a TXT record like
google-site-verification=.... Add it at your domain root.dig +short txt example.com | grep google-site-verification - 02
Verify in PMT
Click "Verify" in the dashboard. Verification usually takes minutes; if it fails, wait 30 minutes and retry — DNS caches lag.
- 03
Wait 48 hours
Data only populates once Google has 48 hours of mail flow attributed to your verified domain. Below ~100 messages/day to Gmail, dashboards stay empty.
The eight dashboards
| Dashboard | What it shows | Action threshold |
|---|---|---|
| Spam rate | % of your mail marked as spam by users | Investigate above 0.1% |
| IP reputation | Per-IP score (Bad/Low/Medium/High) | Anything below High → fix |
| Domain reputation | Per-domain score | Below High → fix |
| Feedback loop | Spammy campaign IDs (requires header) | Any non-zero is investigable |
| Authentication | SPF/DKIM/DMARC pass rates | Below 99% → audit alignment |
| Encryption | TLS pass rate inbound | Below 99% → MTA TLS config |
| Delivery errors | Throttling and rejection rates | Spike → reputation issue |
| Compliance status | Bulk sender rule conformance | Any non-compliant → fix immediately |
Reading domain reputation
Reputation is bucketed: Bad / Low / Medium / High. Movements between buckets are the signal — a steady High is unremarkable; a drop from High to Medium is a fire alarm. The dashboard updates daily but reflects rolling 7-day windows.
| Score | Inbox placement | Typical action |
|---|---|---|
| High | Almost always inbox | Maintain |
| Medium | Mixed — some spam folder | Audit content + complaint trend |
| Low | Mostly spam folder | Pause, fix root cause, re-warm |
| Bad | Universally rejected/spammed | Critical — usually a list source or auth failure |
The Feedback Loop campaign IDs
Gmail's FBL is dashboard-only — but it's per-campaign if you set the Feedback-ID header. Add the header to every send, and PMT will show you which campaigns generate complaints. This is the single most useful diagnostic tool in your kit.
Feedback-ID: <CampaignID>:<CustomerID>:<MailType>:<SenderID>
# Example:
Feedback-ID: spring-promo-2026:cust-1234:marketing:example.comWhen dashboards are empty
- Below ~100 messages/day to Gmail — Google won't display data.
- Recent reputation reset — domain reputation can briefly go blank during resets after a major change.
- Verification expired — re-verify if the TXT record was removed.
- New IP — IP reputation populates only after the IP has been sending for several days.
What PMT doesn't tell you
- Per-message decisions — no log of which messages went to spam.
- B2B vs consumer breakout — all Gmail traffic is mixed in.
- Yahoo, Microsoft, Apple — different receivers, different (or no) tools.
- Inbox placement % — inferred via seed-list services, not exposed by Google.
Frequently asked questions
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