Rapidoid is a collection of web framework modules, including a fast low-level HTTP server implemented from scratch on top of Java NIO. Clever usage of off-heap input/output buffers, object pools and thread-local data structures provide Rapidoid an edge over other NIO-based servers like Netty. Being a fairly new project, Rapidoid has yet to implement a few features like built-in cache and SSL support; we suggest you check the roadmap for updates.