From the Twisted Website:
“Twisted is a framework, written in Python, for writing networked applications. It includes implementations of a number of commonly used network services such as a web server, an IRC chat server, a mail server, a relational database interface and an object broker. Developers can build applications using all of these services as well as custom services that they write themselves. Twisted also includes a user authentication system that controls access to services and provides services with user context information to implement their own security models.
Twisted provides important features needed for networking programming, both at the high and low levels:
– Pluggable event loops allowing the developer to take advantage of platform-specific capabilities.
– Abstractions of protocols and transports.
– Through Twisted Spread, mechanisms for network encoding of data (in Python, Java, ELisp, and other languages), to a full-blown distributed object system.”