How many companies use Office 365 Mail?

TechLeads currently detects Office 365 Mail on 3,817,196 websites.

Who are Office 365 Mail's biggest competitors?

By number of websites, the largest Business Email Hosting technologies besides Office 365 Mail are Microsoft Exchange Online (3,567,170), Titan Email (202,239), Proton Mail (105,300), Namecheap Private Email (83,016), Mimecast (38,769).

Which companies use Office 365 Mail?

Websites using Office 365 Mail include techcrunch.com, justgiving.com, fortune.com, disqus.com, blacklivesmatter.com, globalnews.ca. The full list of 3,817,196 websites can be exported as a CSV for $29.

Office 365 Mail market share and customers

As of October 11, 2026, Office 365 Mail is used by 3,817,196 websites in the TechLeads index: 48.3% of all Business Email Hosting detections, the 1st most-used of 46 Business Email Hosting technologies.

3,817,196

websites using Office 365 Mail

48.3%

share of Business Email Hosting

of 46 in Business Email Hosting

Cite this data

Quoting these numbers? Credit TechLeads with a link to this page.

Citation

TechLeads. "Office 365 Mail Customers and Market Share." Data as of October 11, 2026. https://techleads.fyi/technology/office-365-mail/market-share

HTML link

<a href="https://techleads.fyi/technology/office-365-mail/market-share">Office 365 Mail market share (TechLeads data)</a>

Office 365 Mail vs competitors in Business Email Hosting

Websites using each technology in the TechLeads index, and its share of all Business Email Hosting detections.

#	Technology	Websites	Share
1	Office 365 Mail	3,817,196	48.3%
2	Microsoft Exchange Online	3,567,170	45.1%
3	Titan Email	202,239	2.6%
4	Proton Mail	105,300	1.3%
5	Namecheap Private Email	83,016	1.1%
6	Mimecast	38,769	0.49%
7	SpamExperts

Office 365 Mail customers by country

Based on country-code domains (such as .de or .co.uk); websites on .com and other generic domains are not assigned a country.

US8,484
GB2,921
AU958
DE497
FR467
CA274
BR265
NL187
ES174
JP144

Companies using Office 365 Mail

techcrunch.com · TechCrunch
justgiving.com
fortune.com
disqus.com
blacklivesmatter.com
globalnews.ca
duckduckgo.com
globalwellnessinstitute.org · Global Wellness Institute
variety.com · Variety Australia
udallas.edu
wmrt.com · World Match Racing Tour
boe.es

See all 3,817,196 websites using Office 365 Mail or download the full list as a CSV for $29.

How these numbers are calculated

TechLeads scans public websites and detects Office 365 Mail from signals in the page HTML, scripts, cookies, HTTP headers and DNS records. Market share is Office 365 Mail's website count divided by the website counts of all Business Email Hosting technologies we track; a site using two Business Email Hosting tools counts for both. Counts were last refreshed on October 11, 2026 and update daily.

FAQ

Office 365 Mail accounts for 48.3% of Business Email Hosting detections in the TechLeads index (3,817,196 websites), which makes it the 1st most-used of 46 Business Email Hosting technologies we track.