Free. No account. Nothing stored.
Gmail asks your email two questions.
Your DNS answers the first one. Only Postmaster answers the second.
Is it really you?
Gmail reads three records in your DNS to decide. Type a domain and the answer lands here, in plain words.
Are you welcome?
DNS can’t say.
Only Postmaster can. Gmail counts who marks you as spam and reports it there and nowhere else. Not to Klaviyo. Not to any ESP.
Google’s words: keep it below 0.10% and avoid ever reaching 0.30%, because “maintaining a high spam rate leads to increased spam classification”.
A real domain’s answer, day by day, with the send Google named on each rated day. Names invented, numbers Google’s.
SpamSpike reads this number every day and names the Klaviyo campaign or flow behind every red day.
Find out which send did itThe records, if you want them
What Google requires
SPF
Set up SPF email authentication for your domain.
Learn moreDKIM
Set up DKIM email authentication for your sending domain; keys must be 1024 bits or longer.
Learn moreDMARC
Set up DMARC; the From: domain must align with SPF or DKIM.
Learn moreOne-click unsubscribe
Marketing messages must support one-click unsubscribe with a visible link.
Learn moreTLS and reverse DNS
Transmit over TLS from IPs with valid forward and reverse DNS.
Learn moreSpam rate
“Keep spam rates reported in Postmaster Tools below 0.10% and avoid ever reaching a spam rate of 0.30% or higher.”
Learn more
Every requirement here is Google’s, from Email sender guidelines, read 2026-09-03. The lookup limit is RFC 7208’s. This page performs DNS lookups only: your domain is never fetched and nothing you type is stored.