nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
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.
nginx is leading in Top 10K Sites, Top 100K Sites, Top 1M Sites and The Entire Web.
In terms of market share, Phusion Passenger is clearly lagging behind, losing to nginx in all segments.
nginx has better usage coverage in more websites categories. Including Computers Electronics & Technology, Science & Education, Arts & Entertainment, Health and 20 other categories.
Phusion Passenger hasn't got a lead over nginx in any websites category.
nginx is leading in most countries, including United States, Japan, Russia, China and 162 other countries.
Phusion Passenger hasn't got a lead over nginx in any country.