According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Microsoft 365 is the mailbox provider for 110,268 domains — 16.74% of 658,711 domains with MX records. Detection method: primary MX record (lowest preference).
Microsoft 365 is Microsoft's cloud productivity suite, with Exchange Online as its email platform. Microsoft operates it as a service for organisations ranging from small businesses to enterprises.
Across email infrastructure surveys, Microsoft 365 appears primarily in the long tail of websites rather than dominating the very largest brands. It is geographically distributed across many country-code and generic top-level domains, with .com leading, and carries a global-to-US-skewed presence. It frequently coexists with Amazon SES, reflecting adoption patterns amongst smaller organisations and SMEs. Its share has been growing.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 97 | 0.1% |
| Top 10,000 | 1,053 | 1.0% |
| Top 100,000 | 11,901 | 10.8% |
| Top 1,000,000 | 84,096 | 76.3% |
| Unranked | 13,121 | 11.9% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 47,701 | 43.3% | |
| .org | 6,996 | 6.3% | |
| .de | 4,627 | 4.2% | |
| .co.uk | 3,069 | 2.8% | |
| .nl | 2,897 | 2.6% | |
| .net | 2,518 | 2.3% | |
| .com.br | 2,032 | 1.8% | |
| .com.au | 1,794 | 1.6% | |
| .fr | 1,747 | 1.6% | |
| .ca | 1,591 | 1.4% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 110,268 domains.
| Type | Service | Domains | Share of Microsoft 365 users |
|---|---|---|---|
| ESP | Amazon SES | 9,520 | 8.6% |
| ESP | SendGrid (Twilio) | 9,100 | 8.3% |
| ESP | Mailchimp | 7,271 | 6.6% |
| ESP | Salesforce | 7,034 | 6.4% |
| ESP | Zendesk | 6,885 | 6.2% |
| ESP | Mandrill | 6,447 | 5.8% |
| ESP | HubSpot | 6,379 | 5.8% |
| ESP | Mailgun | 6,185 | 5.6% |
| ESP | Mailjet (Sinch) | 4,066 | 3.7% |
| ESP | Brevo (ex-Sendinblue) | 2,405 | 2.2% |
Microsoft 365 appears frequently alongside Amazon SES in mid-market deployments, reflecting a common architectural pattern: Exchange Online manages organisational inbound mail whilst SES handles transactional or marketing communications. This means senders encounter both recipient-side filtering (Microsoft's authentication and reputation checks) and sender-side infrastructure (SES-based transmission) when engaging with these organisations. Authentication verification is enforced at the Exchange Online layer.
See the full Microsoft 365 data page (KPI cards, trend, sample domains) →
Microsoft 365 (Exchange Online) serves as the mailbox platform for organisational users, particularly in mid-market deployments. It is typically paired with separate sending platforms like Amazon SES for transactional mail, and it enforces strict authentication and reputation-based filtering.
110,268 domains in the Tranco top-1M use Microsoft 365 as their mailbox provider as of July 13, 2026 (16.74% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Microsoft 365 accounts for 16.74% of domains with MX records in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.
Microsoft 365 is growing — its share moved +0.17 pp over the last 30 days (as of July 13, 2026).
Microsoft 365's largest TLD is .com (43.3% of its domains); it appears across 545 TLDs in total.