Reel is a fast, non-blocking "evented" web server built on http_parser.rb, websocket_parser, Celluloid::IO, and nio4r. Thanks to Celluloid, Reel also works great for multithreaded applications and provides traditional multithreaded blocking I/O support too.

Connections to Reel can be either non-blocking and handled entirely within the Reel::Server thread (handling HTTP, HTTPS, or UNIX sockets), or the same connections can be dispatched to worker threads where they will perform ordinary blocking IO. Reel provides no built-in thread pool, however you can build one yourself using Celluloid.pool, or because Celluloid already pools threads to begin with, you can simply use an actor per connection.