Proton is a tool for developing and running web applications for node.js.
Rather than being a web framework in itself, it provides the mechanism for running a web application built on a compatible framework (e.g. micro). Proton is designed to be a thin layer that does not mandate any particular framework.
Once installed, Proton can be used to run a web application via the proton command from the shell. Run proton --help to see a list command line arguments.
Npm is recommended for development, although for production you might want to find/build a package for your operating system:
npm -g install proton
See the Npm folder documentation for more information about the -g switch.
One of the best features of Proton is the ability to pick up changes in your code immediately during development. Just run proton with the -r option and your changes will be immediately apparent.