Cocoon is written in Java and based on the Apache Avalon components framework.
Modular blocks can be enabled by configuration when installing Cocoon, allowing you to have either a small and focused system, or a "kitchen sink" installation with all possible options.
Many of Cocoon's core components and blocks reuse Open-Source libraries, many from other Apache projects and some from outside the Apache Software Foundation.
The caching subsystem uses sophisticated yet very customizable caching algorithms to maximize performance. Although some components or blocks might use a lot of resources (for example when generating PDF documents or bitmapped images), the Cocoon core itself is very efficient and can be tuned to maximize performance under high loads.
Cocoon is distributed under the liberal Apache License which maximises its use while still providing protection.
The Cocoon project lives through its contributors and committers, a community which is recognized for being friendly and efficient. Discussions take place on the mailing lists and IRC channels, and conferences or informal mettings called GetTogethers happen in various places.
The current team comprises more than 40 active committers, of which about 20 are regularly active. Those committers and the wider Cocoon community contribute new components, bug fixes, tests and documentation, and provide user support to each other.