Self-hosted email is in steep decline, Microsoft and Google are taking over

The number of large users hosting their own email servers has halved in the last decade, according to Artem Berezin, a researcher who works at business e-mail company Live Direct Marketing.

On the Internet Society blog, Berezin explained that DNS records reveal a lot about email.

“The MX record says where the mailbox lives.

The SPF record says who may send on the domain's behalf.

The DMARC record says what should happen when a message fails authentication,” he wrote.

Berezin says he analyzes those records using daily forward-DNS snapshots captured by the OpenINTEL project run by the University of Twente, SURFnet and SIDN Labs.

He also consults the Tranco project’s assessment of the most popular domains to determine the million most popular domains, then “classifies each domain's MX hostname and SPF includes against open dictionaries of mailbox providers, sending platforms and SaaS applications.” The data he uses goes back to 2016, but he admits the dictionaries he accesses don’t offer a complete view of the world’s email servers.

His lead finding is that in 2016, 44.6 percent of the top million domains ran their own mail server.

In 2026, that’s down to 22.4 percent.

The number of self-hosted mail servers is falling fast – down by half a percent in 30 days.

Self-hosting an email server remains the most common way to process mail, however Google Workspace is hot on its heels with 21.8 percent of detectable MX records, ahead of Microsoft 365’s 16.8 percent.

Berezin thinks the fact that two tech giants handle 38.6 percent of email is concerning.

“The RIPE [NCC] community has spent years discussing DNS and CDN centralization; email is following the same path, just more quietly,” he wrote.

“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.