Short answer
Google Postmaster Tools is Google's free dashboard for the mail your domain sends to personal Gmail accounts: spam rate, SPF, DKIM and DMARC pass rates, TLS, delivery errors, and whether you meet Gmail's sender requirements. You add your domain at postmaster.google.com, prove you own it with a DNS record, and data appears once you send enough mail to Gmail users.
The number to watch is the user-reported spam rate. Google's sender guidelines require every sender to stay below 0.3% and recommend staying below 0.1%.
On this page
What Postmaster Tools shows, and what it doesn't
Postmaster Tools reports on mail sent to personal Gmail accounts (@gmail.com and @googlemail.com). It doesn't cover Google Workspace recipients, and it says nothing about Outlook.com or Yahoo. Most dashboards count only messages authenticated with DKIM (or SPF where DKIM isn't used) for the domain you add, so mail signed with your provider's domain instead of yours won't show up under your domain.
The data isn't real-time. Google says dashboards usually update within 24 hours, times are in UTC, and days with too little volume are left out to protect user privacy. A small app sending a few dozen messages a day to Gmail users may see nothing at all, and that's normal.
Set it up: add and verify your domain
- 1
Sign in
Go to postmaster.google.com and sign in with a Google account. Ownership is proven with DNS, so the account doesn't have to be an address on the domain you're adding.
- 2
Add the domain you authenticate with
Add a new domain and enter the domain your mail is authenticated with: the DKIM signing domain (the
d=in the DKIM-Signature header) or the SPF return-path domain. If you send fromnotifications@acme.comand sign withacme.com, addacme.com. - 3
Publish the verification record
Postmaster Tools gives you a TXT record (or a CNAME) to prove you own the domain. Add it at your DNS provider exactly as shown, on the root of the domain for a TXT record. It sits next to your SPF record without affecting it.
- 4
Verify
Back in Postmaster Tools, click verify. Google says it's usually immediate but can take up to 10 minutes for the status to change. Until the domain is verified, it shows no data.
- 5
Add subdomains and teammates
Once the root domain is verified, subdomains you add (like
mail.acme.com) don't need their own verification. You can give teammates access to a verified domain from its menu; each needs a Google account.
Check the verification record is live
# Root-domain TXT records: the verification value should appear
# alongside your v=spf1 record
dig +short TXT acme.comWhat each dashboard means
Google rebuilt Postmaster Tools in a newer interface and is retiring the old one, so names and layout may differ slightly from what you see. These are the dashboards Google's help pages describe.
Compliance status
A checklist of Gmail's sender requirements, each marked compliant, needs work, or no data found. The requirements for all senders are SPF and DKIM, valid DNS records (including reverse DNS for the sending IPs), message formatting, TLS encryption and the user-reported spam rate. Bulk senders, about 5,000 or more messages a day to Gmail accounts, are also checked for DMARC, one-click unsubscribe and honoring unsubscribes.
It reports on primary domains only, using subdomain data as an input, and works from a rolling average. Google says a fix can take up to 7 days to show here, so don't expect it to turn green the day you publish a record.
Spam rate
The share of your DKIM-authenticated mail, delivered to the inbox of engaged recipients, that those recipients marked as spam. It's the number Gmail's 0.3% rule refers to.
Read it with one caveat: it only counts mail that reached the inbox. If Gmail is already filtering most of your mail to spam, few recipients see it to report it, and the rate can look reassuringly low while your deliverability is poor. A low spam rate with falling engagement or support tickets about missing emails is a warning sign, not a clean bill of health.
Domain and IP reputation
The original interface rated your sending domain and IPs as High, Medium, Low or Bad. Google is retiring these two dashboards: its deprecation notice says reputation data was hard to act on, slow to reflect changes, and only one of many factors, and that a new reputation view will replace it. The newer Postmaster Tools API doesn't include them either.
Depending on when you read this, you may still see the old ratings or not see them at all. Either way, the spam rate, authentication and delivery error dashboards are the ones to act on.
Authentication
The percentage of mail with your domain in the From header that passed SPF, DKIM and DMARC. Google notes that DKIM and DMARC usually sit at 95% or higher when set up correctly, and that SPF tends to be lower because third-party services send with their own return-path domains. A drop in DKIM or DMARC almost always means a new service is sending as your domain without your DKIM key.
Encryption
The percentage of your authenticated mail sent to Gmail over TLS (outbound), and of mail Gmail sent to your domain over TLS (inbound). Gmail requires TLS from all senders, so outbound should be 100%. Anything less points at a sending server or relay that isn't negotiating TLS.
Delivery errors
The share of your authenticated mail that Gmail rejected or temporarily deferred, with the reasons. Google lists reasons such as rate limiting, suspected spam, content, unsupported attachments, a DMARC reject policy, low reputation, blocklist listings and missing reverse DNS. Errors are grouped into temporary failures and permanent ones.
Feedback loop
Spam rates broken down by campaign, for mail that carries a Feedback-ID header identifying it. It's built for high-volume senders, needs that header set up first, and a campaign only appears once it has gathered a minimum number of spam reports. Most transactional senders can skip it and separate mail streams by subdomain instead.
Thresholds that matter
| Dashboard | Aim for | Act when |
|---|---|---|
| Spam rate | Below 0.1% | It approaches 0.3%. Gmail's sender guidelines say never reach it. |
| Compliance status | Every requirement compliant | Any item shows needs work |
| Authentication (DKIM, DMARC) | 95% or higher | A sudden drop: a new or changed sending service |
| Encryption (outbound) | 100% | Anything below 100% |
| Delivery errors | Near zero | A spike, or permanent failures that name a cause |
The 0.1% and 0.3% figures come from Google's email sender guidelines. The 95% authentication figure is Google's own description of a correctly configured domain.
Last checked on each vendor's public page.
Google's email sender guidelines make 0.3% a requirement for every sender, and set the best-practice target at 0.1%. A spam rate that stays high leads to more of your mail being classified as spam, and Google says improvements take time to show up in filtering. The guidelines also say senders who don't follow best practices may not be considered for deliverability mitigations.
For transactional mail, the realistic target is far lower than 0.1%. People rarely report a password reset they asked for. If your rate climbs, something other than transactional mail is usually in the mix.
What to do when the numbers go bad
Spam rate rising
- Find which mail it is. Complaints about marketing and complaints about password resets land in the same number if they share a domain. Send marketing from a separate subdomain, and add each subdomain to Postmaster Tools so you can see them apart.
- Stop mailing people who didn't ask for it. Unengaged addresses, old imports and anything bought are the usual cause. Make unsubscribing easy on anything that isn't strictly transactional.
- Check sign-up forms for abuse. Bots signing up other people's addresses turn your welcome and verification emails into unsolicited mail. Rate-limit and add a challenge on public forms.
- Give it time. The dashboard lags by about a day, and Google says filtering recovers gradually after the rate comes down.
Authentication dropping
- Run the DKIM checker and DMARC checker on your domain to rule out a broken or rotated record.
- Look for a new sender: a helpdesk, CRM or billing tool that started sending as your domain without your DKIM key. DMARC aggregate reports show every source sending as your domain and whether it passes.
- Set up DKIM for your domain in that service, or move its mail to a subdomain with its own records.
Delivery errors spiking
- Rate limited: you sent faster than Gmail accepts for your reputation. Slow down and let your provider retry; temporary failures are retried automatically by most mail servers.
- Blocklist or low reputation: check the sending IP and your domain with the email blacklist checker, then fix the cause before requesting removal.
- Missing reverse DNS: the sending IP has no PTR record that resolves back. That's set by whoever runs the mail servers, so raise it with your provider.
- DMARC policy: your own mail is failing alignment under
p=quarantineorp=reject. Fix DKIM or SPF alignment for the service that sent it.
Compliance status says needs work
Fix the specific requirement it names. For SPF, DKIM, DMARC and DNS, the domain health check shows what's missing; for formatting and authentication on a real message, use the email deliverability test. Then wait: the rolling average can take up to 7 days to catch up.
Postmaster Tools with Groundmail
Groundmail signs every message with your own domain's DKIM key and sets the return path on your domain, so mail you send through us is attributed to your domain in Postmaster Tools and counts toward its authentication and spam rate figures. Add the domain you send from, verify it, and the data is yours.
Our shared IPs carry transactional mail only, so your password resets don't share an IP with bulk marketing. Bounces arrive as email.bounced webhook events and bounced addresses are suppressed automatically, which keeps you from retrying addresses Gmail has already rejected.
Frequently asked questions
Is Google Postmaster Tools free?
Yes. You need a Google account and a domain you can add DNS records to. There's no fee and no minimum, though low-volume domains may not see data.
Why does Postmaster Tools show no data?
Usually one of four reasons: the domain isn't verified yet, you send too little mail to personal Gmail accounts for Google to report on, you added a domain that isn't the one your mail is DKIM-signed with, or your recipients are on Google Workspace rather than gmail.com, which Postmaster Tools doesn't cover.
What is a good spam rate in Postmaster Tools?
Below 0.1%, which is Google's best-practice target. 0.3% is the line in Gmail's sender requirements that you should never reach. Transactional mail on its own normally sits well below both.
What happened to domain reputation and IP reputation?
Google is retiring those dashboards. Its deprecation notice says reputation was hard to act on and slow to reflect changes, and that a new reputation view will replace it. Use the spam rate, authentication and delivery error dashboards in the meantime.
How do I verify a domain in Postmaster Tools?
Add the domain, copy the TXT (or CNAME) record Postmaster Tools gives you, publish it at your DNS provider, and click verify. It's usually immediate and can take up to 10 minutes.
Do I need Postmaster Tools if I send only transactional email?
It's worth setting up once you send meaningful volume to Gmail users. It's the only place Google shows your spam rate, and Compliance status tells you directly whether you meet Gmail's sender requirements.
Sources
Facts on this page about other companies' products, prices and policies come from these public pages. They change, so check them before you decide.