In 2016, 44.6% of MX-publishing domains in the top million ran their own mail server. In the 18 July 2026 snapshot that figure is 22.4% - and it is still falling, down another half a percentage point in the last thirty days alone.
[…]
The domains didn't disappear; they moved. Google Workspace now receives mail for 21.8% of MX-publishing domains and Microsoft 365 for 16.8%. Together that is 38.6% of the measured Internet's inbound mail behind two companies. Nobody else comes close: the next named provider, Proofpoint, sits at 1.9%.
It is easy to read this as a market-share story, but for this community it is really a resilience story. The RIPE community has spent years discussing DNS and CDN centralisation; email is following the same path, just more quietly. When more than a third of popular domains depend on two providers to receive mail, an outage, a filtering change or a policy decision at either one propagates through the whole ecosystem at once. And unlike a CDN, email has no graceful fallback - a rejected message is simply gone.
There is a second-order effect too. The fewer independent operators there are, the more the remaining ones inherit the deliverability problems of a world tuned for the big two. Anyone who has tried to stand up a fresh Postfix box in 2026 and get its mail accepted at scale knows exactly what I mean.
Two Providers, a Stubborn Plateau and a Very Long Tail: Email in the Tranco Top-1M
for RIPE LabsMail Tester
We generate a random email address each time you access our port.
You should send a message from your favourite Newsletter/email software to this email address.
Once done, click on the Check your score button and as soon as we receive your message, our snail will stop to give you your spam score.
Mail-tester will analyze your message, your mail server, your sending IP... and show you a detailed report of what's configured properly and what's not.