Symfony 2 is a full-stack web framework written in PHP. It is a reusable set of standalone, decoupled, and cohesive PHP components that solve web development problems. Symfony 2 introduced unique HTTP and HTTP cache handling by being an HTTP-centric request or response framework. It also allows full use of advanced features such as ESI to separate the different parts of your page or application.
Symfony 2 is powered out of the box by fast PHP-built Symfony reverse proxy, and for mid to large installations, a seamless upgrade to varnish provides a 10-20x speedup and a far more robust cache handling.
