IIS
1,728,662 websites

IIS offers both free and paid options

http://www.iis.net

A flexible & easy-to-manage web server... Internet Information Services (IIS) for Windows® Server is a flexible, secure and manageable Web server for hosting anything on the Web. From media streaming to web applications, IIS's scalable a...

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Varnish
1,294,354 websites

Varnish is free to use

https://www.varnish-cache.org/

Varnish is an HTTP accelerator designed for content-heavy dynamic web sites. In contrast to other web accelerators, such as Squid, which began life as a client-side cache, or Apache and nginx, which are primarily origin servers, Varnish was...

Market Share by Top Websites

1 IIS is leading in Top 100K Sites, Top 1M Sites and The Entire Web.

2 Varnish is leading in Top 10K Sites.

Websites Categories

1 IIS has better usage coverage in more websites categories. Including Science & Education, Computers Electronics & Technology, Finance, Law & Government and 16 other categories.

2 Varnish is leading in Arts & Entertainment, Food & Drink, Games and Hobbies & Leisure.

Geography

1 IIS is leading in most countries, including China, United Kingdom, Italy, India and 121 other countries.

2 Varnish is leading in United States, Japan, France, Canada and 36 other countries.