Why '98% delivered' doesn't tell the whole story
How do you know if Gmail is delivering your emails? Many senders don't know that Google doesn't report data like spam complaints to ESPs.
How do you know if Gmail is delivering your emails? If your answer is "I check my ESP dashboard", you’re looking in the wrong place.
Most ESP dashboards combine results from all mailbox providers. But Gmail, Microsoft, and Yahoo each decide on their own whether to accept, filter, or block your email. And Gmail is often more than half of a typical list.
Google does share data about how it views your sending domain...but that information only exists inside Google Postmaster Tools.
If you’re not checking Postmaster, you can’t see how Gmail is judging your emails. Your dashboard simply doesn’t have that data.
What your ESP cannot know
Here’s what most people don’t realize: when a Yahoo subscriber marks you as spam, your ESP hears about it.
When a Gmail subscriber does the same thing, your ESP doesn’t.
Gmail keeps that complaint data inside Google.
Early warning signs
A nonprofit came to me after a Giving Tuesday campaign underperformed.
Their dashboard showed high delivery and very few spam complaints. The only red flag was low open and click rates. But low opens can mean a lot of things, so it’s easy to shrug them off.
Inside Google Postmaster Tools, the picture was very different: more than half of the send had been rejected as suspected spam. Domain reputation had dropped from High to Low. Reported spam rate had spiked well above safe thresholds.
Their ESP wasn’t wrong, but it didn't have the full picture.
The low open rate was the symptom. Postmaster Tools showed the cause.
What Postmaster shows you
Google’s published guidance is clear:
- Under 0.1% spam rate is healthy
- Repeated spikes above 0.3% mean likely bulk filtering
If your spam rate is hovering near or above those levels, Gmail is paying attention and your open rates will reflect it before your dashboard can explain why.
Spam rate is just one signal. Postmaster also shows domain reputation trends, authentication alignment, IP reputation (if relevant), and encryption status, all from Google’s perspective.
By default, it’s domain-level data. If your sending identifiers are structured correctly through your ESP, you can even see spam rate by campaign, but that requires setup in advance.
Most senders either don’t know Google Postmaster exists or set it up once and forget it but it's a critical piece of your deliverability puzzle and an important component in my monthly sender reputation monitoring service.