Chassis is a virtual server for your WordPress site, built using Vagrant.
Chassis is basically a way to run WordPress (and related parts, such as PHP and nginx) without needing to worry about setting up anything. You can imagine it as MAMP/WAMP on steroids.
Follow our quickstart instructions to get up and running right away!
We've got tonnes more documentation available at http://chassis.io/ to peruse through at your leisure.
How is Chassis different from VVV?
Each Chassis install is self-contained. We do this to try and mirror the server that you will be deploying to.
Note that while you can't have multiple independent installs on the same Chassis box, we support both subdomain and subdirectory multisite out of the box.
While we certainly can add any feature, consider first if it's better off as a Chassis extension. We try and keep Chassis as lightweight as possible, and extensions are a good way of adding features without weighing down Chassis itself.