Microsoft 365 email provider statistics and deliverability context
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According to Live Direct Marketing's daily Tranco top-1M scan (September 13, 2026), Microsoft 365 is the mailbox provider for 112,783 domains — 16.97% of 664,797 domains with MX records. Over the last 30 days its share grew by 0.20 pp, and -0.01 pp year-over-year. Its strongest TLD is .com (42.9% of its domains). Detection: primary MX record (lowest preference).
Last updated from the 2026-09-13 DNS snapshot.
What Microsoft 365 represents in this dataset
Microsoft 365 / Exchange Online. Default mail platform for Windows-shop enterprises and EU corporate.
Directory category: Mailbox. The classification comes from primary MX record (lowest preference). It describes observed DNS infrastructure, not a commercial relationship and not the placement of any individual message.
What the 2026-09-13 snapshot shows about Microsoft 365
Across 547 distinct TLDs its top three are .com (42.9%), .org (6.2%), .de (4.3%) — together 53.4% of the 112,783 domains, which makes the footprint moderately concentrated, with a recognisable home market. The service most often observed on the same domains is Amazon SES (ESP, 9,635 domains, 8.5% of them), followed by SendGrid (Twilio) (8.2%). Its share of domains with MX records moved +0.20 pp in 30 days, a change larger than list churn alone explains. Directly comparable by the same detection rule: Self-Hosted, Google Workspace, Unknown / Other. Ranking between them reflects what is published in DNS, not delivery quality or volume sent. All figures come from a single daily DNS snapshot (2026-09-13); a domain appears here when its published records match the primary MX record (lowest preference) rule, which is an infrastructure fact, not a commercial relationship.
Commonly used together with Microsoft 365
What else the same 112,783 domains use — cross-tabulated from the same daily snapshot (2026-09-13).
| Type | Service | Domains | Share of Microsoft 365 users |
|---|---|---|---|
| ESP | Amazon SES | 9,635 | 8.5% |
| ESP | SendGrid (Twilio) | 9,211 | 8.2% |
| ESP | Mailchimp | 7,320 | 6.5% |
| ESP | Salesforce | 7,053 | 6.3% |
| ESP | Zendesk | 6,926 | 6.1% |
| ESP | Mandrill | 6,467 | 5.7% |
| ESP | HubSpot | 6,461 | 5.7% |
| ESP | Mailgun | 6,233 | 5.5% |
| ESP | Mailjet (Sinch) | 4,227 | 3.7% |
| ESP | Brevo (ex-Sendinblue) | 2,495 | 2.2% |
TLD distribution (top 30 of 547)
Frequently asked questions
How many domains use Microsoft 365?
112,783 domains in the Tranco top-1M use Microsoft 365 as their mailbox provider as of September 13, 2026, according to Live Direct Marketing's daily DNS scan.
What is Microsoft 365's market share?
Microsoft 365 holds 16.97% of domains with MX records in the Tranco top-1M (snapshot of 2026-09-13). The number is recomputed every day.
Is Microsoft 365 growing or declining?
Microsoft 365's share grew by 0.20 percentage points over the last 30 days (as of September 13, 2026).
What are the biggest alternatives to Microsoft 365?
The largest mailbox providers in the same category by Tranco top-1M share are: Self-Hosted, Google Workspace, Unknown / Other, Generic / unmatched (mx*.*), Generic / unmatched (mail.*) (as of 2026-09-13).
Largest mailbox providers in this category
Self-Hosted (22.38%) · Google Workspace (21.67%) · Unknown / Other (6.61%) · Generic / unmatched (mx*.*) (2.53%) · Generic / unmatched (mail.*) (1.94%) · Proofpoint (1.88%) · Cloudflare Email Routing (1.75%) · Yandex 360 (1.61%) · Mimecast (1.46%) · Hostinger (1.27%)
Domain sample (top 100 by Tranco rank)
Showing 100 of 112,783 domains.