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...

VS

Phusion Passenger
80,695 websites

Phusion Passenger offers both free and paid options

https://www.phusionpassenger.com

Phusion Passenger - a.k.a. mod_rails or mod_rack - is a web server and application server, designed to be fast, robust and lightweight. Administration tools allow you to gain insight into web application operations and server performance.

Market Share by Top Websites

1 IIS is leading in Top 10K Sites, Top 100K Sites, Top 1M Sites and The Entire Web.

2 In terms of market share, Phusion Passenger is clearly lagging behind, losing to IIS in all segments.

Websites Categories

1 IIS has better usage coverage in more websites categories. Including Science & Education, Computers Electronics & Technology, Finance, Law & Government and 20 other categories.

2 Phusion Passenger hasn't got a lead over IIS in any websites category.

Geography

1 IIS is leading in most countries, including United States, China, United Kingdom, Italy and 161 other countries.

2 Phusion Passenger is leading in Turkmenistan.