Mongrel (web server)

Mongrel is an open-source software HTTP library and web server written in Ruby by Zed Shaw. It is used to run Ruby web applications and presents a standard HTTP interface. This makes layering other servers in front of it possible using a web proxy, a load balancer, or a combination of both, instead of having to use more conventional methods employed to run scripts such as FastCGI or SCGI to communicate. This is made possible by integrating a custom high-performance HTTP request parser implemented using Ragel.

Mongrel was the first web server used by Twitter, and inspired Node.js according to Ryan Dahl.

Shaw subsequently created Mongrel2, an open-source "language agnostic" web server and the successor to Mongrel server.