Microsoft 365 China email service provider (ESP)
According to Live Direct Marketing's daily Tranco top-1M scan (September 14, 2026), Microsoft 365 China is the email service provider (ESP) for 152 domains — 0.02% of 637,677 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 152 domains in the Tranco top-1M use Microsoft 365 China (0.02% of SPF-publishing domains).
- Snapshot date: 2026-09-14 — recomputed every day.
- Strongest TLD: .com (56.6% of its domains).
- Most co-used service: Unknown / Other.
- Directory category: email security gateway.
Why Microsoft 365 China appears in this category
Microsoft 365 — China (operated by 21Vianet).
We classify it as a email security gateway from include: mechanisms in the SPF record matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
Microsoft 365 China is Microsoft's cloud-hosted productivity platform for the Chinese market, offering email, calendar, and collaboration tools. It is operated by Microsoft in compliance with China's regulatory requirements for cloud service providers and data residency.
The SPF footprint for Microsoft 365 China appears concentrated in the long tail of smaller websites rather than major enterprises, predominantly on .com domains and often alongside less common SPF mechanisms. This pattern suggests Microsoft 365 China attracts smaller or less mainstream email senders, which can affect how mail systems categorise and route messages from these domains.
Where Microsoft 365 China sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 1 | 0.7% |
| Top 10,000 | 7 | 4.6% |
| Top 100,000 | 30 | 19.7% |
| Top 1,000,000 | 114 | 75.0% |
| Unranked | 0 | 0.0% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 86 | 56.6% | |
| .cn | 27 | 17.8% | |
| .com.cn | 22 | 14.5% | |
| .io | 4 | 2.6% | |
| .net | 3 | 2.0% | |
| .com.br | 2 | 1.3% | |
| .com.hk | 1 | 0.7% | |
| .ai | 1 | 0.7% | |
| .org | 1 | 0.7% | |
| .jp | 1 | 0.7% |
What Microsoft 365 China users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 152 domains.
| Type | Service | Domains | Share of Microsoft 365 China users |
|---|---|---|---|
| Mailbox | Unknown / Other | 108 | 71.1% |
| Mailbox | Self-Hosted | 22 | 14.5% |
| Mailbox | Lark / Feishu (ByteDance) | 4 | 2.6% |
| Mailbox | Google Workspace | 3 | 2.0% |
| Mailbox | QQ Mail (Tencent) | 3 | 2.0% |
| Mailbox | Microsoft 365 | 2 | 1.3% |
| ESP | Zendesk | 9 | 5.9% |
| ESP | Alibaba DirectMail | 5 | 3.3% |
| ESP | Mandrill | 5 | 3.3% |
| ESP | Salesforce | 4 | 2.6% |
SPF Include Patterns and Reputation Friction in the Long Tail
Domains using Microsoft 365 China SPF includes typically cluster alongside other less common authentication mechanisms, a pattern that can disadvantage senders when receiving systems encounter unfamiliar SPF configurations. Mail systems may apply stricter filtering to such domains, even when the underlying authentication is valid; maintaining a clean, minimal SPF record and avoiding redundant includes improves deliverability for smaller senders using this platform.
See the full Microsoft 365 China data page (KPI cards, trend, sample domains) →
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Frequently asked questions
What is Microsoft 365 China SPF, and how does it affect email delivery?
Microsoft 365 China is a cloud email platform used primarily by smaller sites; domains using its SPF includes typically appear alongside other less common authentication mechanisms. This long-tail concentration may result in tighter filtering from receivers unfamiliar with the pattern, so senders should verify their SPF syntax is clean and minimise redundant authentication mechanisms.
How many domains use Microsoft 365 China?
152 domains in the Tranco top-1M use Microsoft 365 China as their email service provider (ESP) as of September 14, 2026 (0.02% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is Microsoft 365 China common enough to affect email deliverability testing?
Microsoft 365 China accounts for 0.02% of SPF-publishing domains 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.
Which countries or TLDs use Microsoft 365 China most?
Microsoft 365 China's largest TLD is .com (56.6% of its domains); it appears across 14 TLDs in total.