Key takeaways
- Postmaster Tools is free and shows how Gmail sees mail from your domain.
- You verify ownership with a DNS TXT record, usually in under an hour.
- Data only appears once you send a meaningful daily volume to Gmail users.
- The spam rate chart and the compliance status are the two views to check first.
- Google is retiring the old domain and IP reputation dashboards; focus on spam rate, authentication and compliance.
In this guide
- What Google Postmaster Tools is (and is not)
- Who should set it up
- How to set up Postmaster Tools step by step
- The dashboards and what each one tells you
- A 10-minute weekly routine
- How to react to what you see
- Common mistakes with Postmaster Tools
- Postmaster Tools in your wider deliverability toolkit
- Frequently asked questions
What Google Postmaster Tools is (and is not)
Google Postmaster Tools is a free service from Gmail that shows senders how their mail performs at Gmail: how often users report it as spam, whether it passes authentication, whether it meets Gmail's sender requirements, and why some messages are rejected. It is the closest thing you get to looking over Gmail's shoulder.
It is not an email testing tool. It does not tell you whether one particular campaign landed in the inbox, and it does not show data for other providers such as Outlook or Yahoo. It shows aggregated, daily data about traffic from your domain to personal Gmail accounts.
For anyone sending marketing or transactional email at scale, it is mandatory. In every deliverability audit I run, it is the first tool I open, because Gmail is usually the biggest provider on the list and the one with the strictest rules.
Who should set it up
- Every business that sends newsletters or promotions, even small ones. Setup takes minutes, and the history is valuable the day something goes wrong.
- Online shops, because order confirmations and abandoned cart emails depend on Gmail trust too.
- Agencies, for each client domain they manage.
- Anyone who received a warning from their email platform about complaints or bounces.
Gmail only shows data when your domain sends enough daily traffic to Gmail users. If you send a few dozen emails a week, charts may stay empty. Set it up anyway: data appears automatically when your volume grows.
How to set up Postmaster Tools step by step
- Sign in at postmaster.google.com with a Google account. A personal Gmail account works; a Google Workspace account is fine too.
- Add your domain. Enter the domain used in your From address, for example
yourbrand.com. If you send from a subdomain such asnews.yourbrand.com, you can add the parent domain to see combined data, or the subdomain itself for more detail. - Copy the verification record. Google gives you a TXT record that starts with
google-site-verification=. - Add it to your DNS. In your domain host's DNS zone (for example your hosting control panel), create a TXT record on the root of the domain with that value. Do not delete your SPF record: a domain can have several TXT records, but only one of them can be SPF.
- Click Verify. DNS changes can take from a few minutes to a few hours. If verification fails, wait and try again.
- Add colleagues if needed. You can share access with other Google accounts, which is useful for agencies and teams.
Verification is permanent as long as the TXT record stays in place. If someone cleans up your DNS later and removes it, you lose access, so leave a note in your DNS documentation.
The dashboards and what each one tells you
Google has been moving Postmaster Tools to a new version. The interface now focuses on compliance with sender requirements, and Google announced the retirement of the old domain and IP reputation dashboards, because reputation alone was hard for senders to act on. The other dashboards remain. Here is how to read them.
| Dashboard | What it shows | What to watch |
|---|---|---|
| Compliance status | Whether your domain meets Gmail's sender requirements | Any requirement marked as not compliant |
| Spam rate | Share of inbox-delivered mail that users reported as spam | Stay under 0.1%; never reach 0.3% |
| Authentication | Share of traffic passing SPF, DKIM and DMARC | Anything below almost 100% for your own streams |
| Encryption | Share of mail sent over TLS | Should be close to 100% |
| Delivery errors | Rejected and temporarily failed messages, with reasons | Sudden spikes, authentication or rate-limit errors |
| Feedback loop | Spam reports by campaign identifier, for senders who set the Feedback-ID header | Campaigns or streams with unusual complaint levels |
Compliance status
This view summarizes the requirements Gmail applies to senders: SPF and DKIM, DMARC for bulk senders, alignment of the From domain, valid reverse DNS, TLS, a low spam rate and one-click unsubscribe for marketing mail. If one line is not compliant, fix it first. Everything else depends on it. My guide to SPF, DKIM and DMARC covers the authentication part, and the one on one-click unsubscribe covers the header requirement.
Spam rate
This is the most important number. It is calculated on messages delivered to the inbox: of those, how many did users mark as spam? Mail already filtered to spam does not count, which means a spam rate that looks low can hide a problem if a lot of your mail never reaches the inbox in the first place.
Read it as a trend. A single day at 0.2% after a big promotion is a warning. Several days above 0.3% is an emergency: Gmail says senders above that level are not eligible for mitigation until they stay below it for seven consecutive days.
Authentication
This chart shows the percentage of your traffic that passed SPF, DKIM and DMARC. For your own legitimate streams, it should be very close to 100%. If DKIM success suddenly drops, a sending tool probably lost its DKIM setup, or a new tool was added without it. To find which one, use your DMARC aggregate reports.
Delivery errors
Here you see rejected or temporarily refused messages and the main reasons: rate limiting, suspected spam, authentication problems, bad reputation. A spike of authentication errors usually goes together with 550 5.7.26 bounces in your platform.
A 10-minute weekly routine
- Open the compliance status. Everything compliant? Move on. Anything red? Fix it today.
- Check the spam rate for the last 7 and 30 days. Note any day above 0.1% and match it with the campaign you sent that day.
- Look at authentication. Any drop means a sending source broke. Find it before it causes bounces.
- Scan delivery errors. A new type of error is more important than a stable, low level of old ones.
- Write down what you saw. A simple note per week builds a history that makes future problems much faster to diagnose.
How to react to what you see
| What you see | Likely cause | What to do |
|---|---|---|
| Spam rate rising after one campaign | Sending to old or unengaged contacts, or an unexpected offer | Pause that segment, check consent and targeting |
| Spam rate high on every campaign | List source or frequency problem | Review where contacts come from, reduce frequency, run a re-engagement |
| DKIM pass rate drops | A tool sends without DKIM on your domain | Check DMARC reports, authenticate that tool |
| Delivery errors for rate limiting | Volume spike from a new domain or after a pause | Spread sends over time, warm up gradually |
| Compliance: unsubscribe not compliant | Missing one-click headers on marketing mail | Enable list-unsubscribe headers in your platform |
| Charts empty | Volume too low to Gmail users | Normal; rely on bounces, complaints and seed tests |
When the spam rate climbs, the cause is almost always the list, not the content. Old contacts who forgot you, purchased data, or subscribers who never confirmed. Cleaning the list and sending only to engaged people is the fix; see my step-by-step list cleaning guide.
Common mistakes with Postmaster Tools
- Adding the wrong domain. Add the domain your subscribers see in the From address, and the one that signs DKIM if your platform uses a different one.
- Deleting the SPF record while adding the verification record. Add a new TXT record; never replace the SPF one.
- Checking only after a problem. Without a baseline, you cannot tell what changed.
- Ignoring the spam rate because it is "below 0.3%". The target is under 0.1%. Between the two, you are already in a risk zone.
- Treating Gmail as the whole picture. Outlook and Yahoo have their own rules. See Outlook-specific fixes and Yahoo's requirements.
Postmaster Tools in your wider deliverability toolkit
Postmaster Tools is one signal among several. Combine it with:
- Your email platform's reports: bounces, complaints and clicks by campaign and by provider.
- DMARC reports: who sends with your domain and whether they pass.
- Seed tests: where a specific campaign lands at each provider. See how to run an inbox placement test.
- Blocklist checks: monthly, or after a sudden drop. See how to check blocklists.
Together, these give you a reliable view of your sender reputation, even without the old reputation charts.
Frequently asked questions
Is Google Postmaster Tools free?
Yes. Any sender can use it with a Google account, as long as they can prove ownership of the domain by adding a DNS record.
Why does Postmaster Tools show no data?
Gmail only shows data when your domain sends enough daily traffic to personal Gmail accounts. Small senders may see empty charts on many days. That is normal, not an error.
Which domain should I add to Postmaster Tools?
Add the domain used in your visible From address and the domain that signs DKIM if it is different. If you send from a subdomain, you can add the parent domain and see aggregated data.
Does Postmaster Tools work for Outlook or Yahoo?
No. It only covers Gmail. Microsoft offers SNDS for IP data, and Yahoo provides a complaint feedback loop.
How often should I check Postmaster Tools?
Once a week is enough in normal times, and daily after a big campaign, a list import or a change in your sending setup.
