Self-hosted email is in steep decline, Microsoft and Google are taking over
Self-hosted email is declining rapidly, with Microsoft and Google increasingly dominating how domains receive mail, according to research by Artem Berezin of business e-mail company Live Direct Marketing, published on the Internet Society blog. This matters because it concentrates control over global email delivery in the hands of two companies, meaning an outage, filtering change, or policy shift at either could disrupt communication across much of the internet, with no fallback if a message is rejected.
Berezin's analysis of DNS records, using daily snapshots from the OpenINTEL project and Tranco's list of top domains, found that the proportion of the top million domains running their own mail server fell from 44.6 percent in 2016 to 22.4 percent in 2026, and is still dropping by roughly half a percent every 30 days. Google Workspace now handles 21.8 percent of detectable mail servers and Microsoft 365 16.8 percent, meaning the two firms together manage 38.6 percent of email delivery. Berezin also warned that over half of DMARC anti-spoofing records remain unenforced despite 2024 mandates from Google and Yahoo, and that smaller mail operators increasingly struggle with deliverability in a system tuned to favour the two giants.
- Self-hosted email fell from 44.6% to 22.4% of top domains since 2016.
- Google and Microsoft now handle 38.6% of email between them.
- Researcher warns of systemic risk and poor DMARC enforcement.
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Email can be run by an organisation on its own servers or handled by an outside provider. Google Workspace and Microsoft 365 are services that manage email for organisations, including receiving messages sent to their web domains.
The Domain Name System (DNS) records used in the research show where a domain’s incoming email is directed. DMARC is a standard that helps domain owners tell receiving services how to handle messages that may be pretending to come from them.
The shift matters because organisations may rely on a small number of providers to deliver email. If one changes its rules or has an outage, messages could be delayed or rejected; smaller providers can also find it harder to get their mail delivered.
Both sides, in good faith
The strongest fair case each way — we don't pick a winner.
The case for
The consolidation reflects legitimate market preferences: large email providers invest substantially in infrastructure, security, and spam filtering that individual organisations struggle to maintain at comparable quality and cost. Self-hosting email is technically demanding, expensive, and often leaves organisations vulnerable to security breaches and poor deliverability. Large providers have economies of scale and security teams that smaller operators cannot match, ultimately protecting users more effectively against evolving threats.
The case against
The concentration of email infrastructure in two companies creates unacceptable systemic risk for global communications, as an outage, filtering change, or policy shift at either provider could disrupt messages for much of the internet with no alternative route. Smaller organisations and operators lose autonomy and become subject to corporate policies where incentives may not align with users' needs. This concentration also enables potential censorship at scale and creates dangerous dependencies on corporate benevolence and operational stability.