Phusion Passenger is a web server and application server, designed to be fast, robust and lightweight. It takes a lot of complexity out of deploying web apps, adds powerful enterprise-grade features that are useful in production, and makes administration much easier and less complex. Phusion Passenger supports Ruby, Python, Node.js and Meteor.

What makes it so fast and reliable is its C++ core, its zero-copy architecture, its watchdog system and its hybrid evented, multi-threaded and multi-process design.