Google Postmaster Tools, Explained

Google Postmaster Tools (GPT) is the only place Gmail tells you, in its own numbers, how it treats your mail. It is free, it is keyed to the domain you authenticate with, and for high-volume senders it is effectively mandatory - Gmail’s bulk-sender rules are written around a spam rate you can only see here. This page covers what each dashboard reports and, more usefully, where senders misread them. Every claim below is from Google’s own Help Center.

The 60-second version

• GPT reports only on mail to personal Gmail accounts - addresses ending in @gmail.com or @googlemail.com. Google Workspace recipients are not included.
• You add the DKIM (d=) domain or the SPF (Return-Path) domain and verify ownership with a DNS TXT record. Without verification, no data appears.
• There are eight dashboards: Compliance status, Spam rate, IP Reputation, Domain Reputation, Feedback loop, Authentication, Encryption, and Delivery errors.
• The Spam rate is user-reported spam on DKIM-authenticated mail that reached an engaged inbox - it is the number Gmail’s guidelines target (keep it below 0.10%, never reach 0.30%).
• Data is not real-time (typically within 24 hours; a compliance change can take up to 7 days) and uses UTC. Low-volume days may show no data, by design.
• The Feedback loop is campaign-aggregate - it never identifies an individual recipient.

Setting it up: domain and DNS verification

You need a Google or Google Workspace account. In Postmaster Tools you click Add and enter the domain you authenticate outgoing mail with. Google’s instruction is precise: add either the DKIM (d=) domain or the SPF (Return-Path) domain. If the DKIM and SPF domains are the same, Postmaster Tools uses messages signed by SPF, DKIM, or both for the dashboards.

Verification is a single DNS record:

# Google supplies a TXT value; publish it on the domain you added.
example.com.  3600  IN  TXT  "google-site-verification=XXXXXXXXXXXXXXXXXXXXXXXX"

Click Verify. Google states domains are “verified right away but it might take up to 10 minutes.” You can skip verification, but then “Postmaster Tools won’t display information about your email until your domain is verified.”

Two setup details that trip people up:

• Subdomains. Add a subdomain the same way you add a primary domain if you want to see it independently. But “If the primary domain is verified, you don’t need to verify its subdomains” - subdomain data still flows into the primary domain’s dashboards.
• Multiple users. Owners can grant other Google/Workspace accounts access to a verified domain. Google does not notify the person automatically, so tell them.

The eight dashboards

1. Compliance status

This is the dashboard Gmail added so the receiver can grade you against its own sender requirements. It is available to all senders, where a bulk sender is “any sender that sends about 5,000 messages or more to Gmail accounts in a 24-hour period.”

It reports requirement-by-requirement:

Shown for all senders	Shown only for bulk senders
SPF and DKIM authentication	DMARC authentication
DNS records	One-click unsubscribe
Message formatting	Honor-unsubscribe
Encryption
User-reported spam rate

Each requirement reads as Compliant, Needs work, or No data found. Two things to know:

• It reports for primary domains only. Google: “The dashboard uses data from subdomains to determine compliance, but provides status for primary domains only.” If you added email.solarmora.com, the status shows for solarmora.com.
• It lags. After you fix something, “it can take up to 7 days for changes to be reflected.” The “Honor unsubscribe” entry specifically flags if you do not remove recipients within 48 hours - and Google warns that “Successful unsubscribe requests count toward your compliance rate whether or not your servers receive it,” so a CDN (their example: Cloudflare) blocking the request still counts against you.

2. Spam rate

The most important number here, and the most misread. Google’s definition: “the percent of your messages that are delivered to engaged recipient’s Inbox and then marked as spam by the recipient.” It is computed on DKIM-authenticated messages.

The trap is the denominator. If Gmail is already auto-routing your mail to spam, fewer messages reach an inbox to be reported, so the displayed rate can look deceptively low. Google says it directly: “If Gmail automatically sends a significant number of your messages to spam, the rate shown in the dashboard might seem low.” A spam rate that suddenly drops to near zero is often a symptom of bulk foldering, not a win.

The numeric targets are not on this dashboard - they live in the sender guidelines: keep the rate below 0.10% and never reach 0.30%. After remediation, Google says to “wait up to 7 days for the spam rate to reach a level that falls within compliance.”

3 & 4. IP Reputation and Domain Reputation

Reputation is “a rating of the quality of domains and IP addresses used to send email.” Google publishes it on a four-tier scale, and the exact wording matters:

Rating	Google’s definition
Bad	”History of sending a high volume of spam regularly. Email from this domain or address is almost always marked as spam or rejected by the receiving server.”
Low	”History of sending a significant volume of spam regularly. Email from this domain or address is likely to be marked as spam.”
Medium	”History of sending legitimate email, but occasionally sends spam. Most email… has a fair deliverability rate, except when there’s a notable increase in spam.”
High	”History of very low spam rates, and complies with Gmail’s sender guidelines. Email from this domain or address is rarely marked as spam by Gmail.”

Reputation is shown for domains and IPs that send DKIM-authenticated mail; if you do not use DKIM, it falls back to SPF-authenticated mail. The Domain Reputation dashboard “only displays messages sent from the exact domain used for DKIM and SPF authentication” - so a misaligned signing domain can leave it sparse. To improve a rating, Google’s advice is blunt: stop sending spam and unauthenticated mail, and reduce your spam rate.

5. Feedback loop

Gmail’s FBL is different from Microsoft’s and Yahoo’s, and the difference is the whole point. It “displays the spam rate for email campaign messages that have a feedback loop ID” - the ID identifies the campaign, not the recipient. You set it up by embedding a campaign identifier in your mail; the dashboard then shows an Average FBL spam rate per campaign over time.

It is aggregate by design: “To show in this dashboard, a minimum number of spam reports for the Feedback Loop ID is required.” You can view it by From header domain or All signed domains. You will never get a recipient’s address out of Gmail’s FBL - for identifiable complaint copies you need Microsoft JMRP or Yahoo CFL (see Microsoft SNDS & JMRP and Yahoo Sender Hub & CFL).

6. Authentication

Shows “the percent of your email that passes SPF, DKIM, and DMARC,” for messages with your sending domain in the From: header. Google offers a useful baseline: “Senders typically achieve 95% or higher success rates for DKIM and DMARC when these methods are set up correctly. SPF success rates tend to be lower” - largely because forwarding and third-party senders break SPF alignment more often than DKIM.

One caveat to read correctly: when you choose View by DKIM and SPF domains, “the dashboard does not show the DMARC success rate.” So a low DMARC number and a “missing” DMARC number can mean different views, not different problems. For what DMARC actually proves, see DMARC in 2026.

7. Encryption

Two figures: TLS inbound (percent of incoming Gmail traffic over TLS) and TLS outbound (percent of your outgoing mail to Gmail over a secure connection). If you send 100% over TLS but the dashboard shows less, Google’s listed causes are forwarders that drop TLS or replay/spoof attempts hitting old messages. A flat 0% usually means an invalid/expired certificate or an unsupported TLS version.

8. Delivery errors

The percent of authenticated messages (SPF or DKIM) that were rejected or temporarily failed, with volumes and reasons. The reason labels are a compact diagnostic vocabulary; Google documents these among them:

• Rate limit exceeded - sending too fast; slow down and send at a constant rate.
• Suspected spam / Email content is possibly spammy - usually low reputation or content.
• DMARC policy of the sender domain - your p=reject is being applied to mail that fails DMARC.
• Sending IP / domain has a low reputation.
• Domain is in one or more public RBLs / IP is in one or more public RBLs.
• Bad or missing PTR record - the sending IP has no reverse DNS.

If the dashboard’s failure rate is higher than your own logs show, Google notes the gap is often forwarded mail (the forwarder gets the errors) or DKIM-replay attempts on old messages.

What it will not tell you

• Folder placement. GPT reports perception (spam rate, reputation, errors), not whether you hit Inbox, Promotions, or Spam. The spam-rate masking effect above is the clearest example.
• Individual complainers. The Feedback loop is campaign-aggregate; there is no recipient identity.
• Workspace mail. Data “only applies to messages sent to personal Gmail accounts.”
• Anything, when you are small. “To protect the privacy of Gmail users, the dashboard might not include all data on days when outgoing email volume is low.” New senders routinely see blanks.
• Right now. It is not real-time; expect ~24 hours of lag and up to 7 days for compliance and spam-rate changes to settle, all in UTC.

What this means for you, and what Egressif does

Read GPT as an early-warning system for the inputs to placement - complaints, authentication, reputation, errors - not as a placement report. And read the spam rate with the masking caveat in mind: a number that looks too good after a bad week is a flag, not a recovery.

Egressif verifies clients’ sending domains into Postmaster Tools, watches the Spam rate against Gmail’s 0.10% / 0.30% lines, tracks Authentication and Delivery-errors for drift the moment a new source or DNS change degrades a pass rate, and uses the four-tier reputation as corroboration rather than the headline. We treat a “Needs work” on Compliance status as an action item with an owner. We do not promise inbox placement; we make sure Gmail’s own signals are visible and acted on before they turn into throttling.