Gmail Postmaster Tools is the single most-actionable deliverability dashboard for any sender targeting consumer inboxes. It's free, it covers ~30 % of most B2C lists, and it surfaces six distinct signals that map cleanly to corrective actions. An AcelleMail operator who isn't watching Postmaster Tools daily during warmup is operating blind.
This walkthrough covers verification, every graph, what each one means in practice, and the AcelleMail action when something drops.
Step 1 — Verify your sending domain#
Open postmaster.google.com, click Add Domain, enter your sending domain (e.g. mail.example.com or example.com), and copy the verification TXT record:
TXT example.com google-site-verification=<token>
Add to your DNS, click Verify. Propagation: typically immediate, sometimes up to an hour. Postmaster needs DKIM-authenticated traffic from this domain to begin showing data — verification alone gives you the dashboard structure but no graphs until Gmail sees aligned traffic. Plan to wait 24-48 hours after your first DKIM-authenticated send before expecting data.
A subtle gotcha: verify the organizational domain, not just the subdomain. If you send from mail.example.com, also verify example.com — Gmail's reputation graphs aggregate at the organizational level, and you want both views.
Step 2 — The 6 graphs#
Graph 1 — IP Reputation#
Per-IP graph showing "High / Medium / Low / Bad" over time. The single most-load-bearing reputation metric.
- High — emails from this IP go to the inbox by default.
- Medium — most go to the inbox; some go to spam based on per-message content.
- Low — most go to spam; only the highest-engagement messages inbox.
- Bad — emails from this IP are rejected before classification.
Action per state:
| State |
Action |
| High → Medium |
Investigate within 24h. Check the last 3 campaigns for any unusual content/audience. |
| Medium → Low |
Pause new volume immediately. Send only to engaged-30-day segment for 7 days. Review FBL data for content cause. |
| Low → Bad |
Stop all sending from this IP for 14-21 days. Continued sending into Bad extends the cool-down period 2-3×. |
| Bad → recovery |
After 14-21 day pause, restart at 5 % of previous volume, ramp slowly per the warmup schedule. |
Graph 2 — Domain Reputation#
Per-domain graph, same scale as IP. Increasingly weighted higher than IP reputation for B2C senders.
The domain reputation lifts and drops on different signals than IP:
- Authentication consistency (SPF + DKIM + DMARC alignment) lifts domain reputation.
- From-address consistency (same
From: line over time) lifts.
- Engagement of recipients on this domain's mail (regardless of IP) lifts.
- Sudden from-domain churn drops it.
When IP reputation is High but Domain is Medium, the corrective is on-domain consistency — stabilize the from-address line, make sure DMARC is aligned, audit DKIM key rotation timing.
Graph 3 — Spam Rate#
The percentage of your delivered email that Gmail users marked as spam (over a 7-day rolling window).
- < 0.10 % — healthy, no action.
- 0.10 - 0.30 % — yellow zone. Review recent campaigns.
- > 0.30 % — danger. Reputation will drop within days.
Action when spam rate spikes:
- Identify the campaign that caused it (Postmaster doesn't say which campaign — look at AcelleMail dashboard for the sends in that window).
- Check unsubscribe-link visibility, subject-line accuracy, content-vs-permission match.
- Suppress the audience that complained (FBL via JMRP plus Gmail-internal complaints aren't surfaced — see FBL setup).
- Reduce frequency for the affected segment.
Graph 4 — IP Reputation Per IP (drill-down)#
Same as Graph 1 but with per-IP detail when you have multiple. Useful for multi-server senders to identify which IP needs attention. The corrective actions are per-IP.
Graph 5 — Authentication#
Per-protocol pass rate:
- SPF Pass Rate — should be 100 %. < 99 % = something is wrong with SPF.
- DKIM Pass Rate — should be 100 %.
- DMARC Pass Rate — should be 100 % once you have aligned both.
When any drops below 100 %, the corrective is technical (DNS / authentication setup), not reputation. Use dig to verify each record is published correctly.
Graph 6 — Encryption#
Percentage of mail sent over TLS. Should be 100 % for any modern AcelleMail install. < 100 % usually indicates a sending server with a misconfigured TLS context — check the AcelleMail sending server "Use TLS" setting.
Step 3 — Set up alerts#
Gmail Postmaster doesn't have native email alerts (frustratingly). For automated monitoring, two options:
Option A — Manual daily check. Add a 5-minute slot to your morning routine. Good enough for Small-tier senders.
Option B — Programmatic export. Postmaster Tools has no API, but the dashboard is iframe-able. Use a headless-browser script (Playwright) to scrape daily and push to your own dashboard. Engineering effort: ~4 hours initial + ~30 min/quarter maintenance.
Most operators stick with manual daily checks until they cross 1M sends/month.
Per-AcelleMail-event correlation#
When IP reputation drops, find the cause:
-- Did we send anything unusual in the last 7 days?
SELECT
c.name as campaign,
c.subject,
COUNT(tl.id) as sent,
SUM(CASE WHEN bl.bounce_type = 'unknown' THEN 1 ELSE 0 END) as complaints
FROM campaigns c
JOIN tracking_logs tl ON tl.campaign_id = c.id
LEFT JOIN bounce_logs bl ON bl.tracking_log_id = tl.id
WHERE c.created_at > NOW() - INTERVAL 7 DAY
GROUP BY c.id
HAVING complaints * 1.0 / sent > 0.001 -- > 0.1% complaint rate
ORDER BY complaints DESC;
Campaigns above this complaint-rate threshold likely caused the Postmaster signal.
Common patterns#
| Postmaster signal |
AcelleMail-side cause |
| Spam Rate jumps to 0.5 % |
Single campaign with bad content/audience match — find it via SQL above |
| IP rep drops Medium → Low |
Sustained complaint or bounce-rate elevation over 5-7 days |
| Authentication SPF drops |
DNS change broke SPF (e.g. third-party tool added a sender that's not in SPF) |
| Authentication DKIM drops |
Key rotation timing — selector mismatch between AcelleMail's signed key and DNS-published |
| Domain rep Medium when IP is High |
From-address inconsistency or DMARC misalignment |
Related reading#
FAQ#
How long after first sending will Postmaster show data?#
24-48 hours minimum. New domains may take up to 7 days. If still empty after a week with verified DKIM-authenticated traffic, your DKIM may not be aligning correctly — check Postmaster's "Authentication" tab for SPF/DKIM/DMARC pass rates.
What's the difference between IP and Domain reputation?#
IP reputation is per-sending-IP; Domain is per-from-domain. Both are scored "High/Medium/Low/Bad" but on different signals. For B2C senders in 2026, Domain reputation matters more than IP.
Can I get historical data older than the dashboard shows?#
No, Postmaster Tools shows a rolling 30-90 days only. For longer-term tracking, scrape daily and store yourself.
Why doesn't my Gmail-only test list show up in Postmaster?#
Postmaster requires a minimum volume of authenticated mail to start showing graphs — typically 100+ messages/day to Gmail-aware recipients. A test list of 5 addresses won't trigger data display.
A monthly Postmaster review template#
The first Friday of each month, dedicate 30 minutes to a cross-domain Postmaster review:
- For each verified domain in Postmaster, take a screenshot of every graph. Archive in
ops/postmaster-screenshots/<YYYY-MM-DD>/. Postmaster only retains 30-90 days; your archive becomes the long-term record.
- Compare the current month vs the previous month for each graph. Note:
- Is IP reputation trending up, flat, or down?
- Is Domain reputation tracking IP, leading, or lagging?
- Is Spam Rate stable, drifting up, or spiking?
- Is Authentication consistently 100 %?
- For any drift, identify the AcelleMail-side cause:
- New campaign type → audit the campaign for content/audience match.
- New sending server → check warmup status.
- New from-address → verify DKIM alignment.
- Volume change → check if it was planned and within historical patterns.
- Document in a deliverability log so the next operator (or future-you) has the context.
What to do when Postmaster shows nothing#
Three reasons for empty Postmaster graphs even after 7+ days:
- DKIM not aligning — verify by sending a test to a Gmail address you control, then in Gmail click "Show original" on the received message. Look for
DKIM: PASS and the signing domain. If the signing domain doesn't match your verified Postmaster domain, alignment is broken.
- Volume too low — Postmaster needs ~100 daily authenticated messages from the verified domain to populate graphs. Test programs sending < 100/day to Gmail won't show data.
- Verification expired — Postmaster occasionally expires verifications when the TXT record is removed or the domain isn't authoritative. Re-verify if the dashboard shows "Domain unverified."
