Sitecore Foundation provides a couple of utility classes that streamline the process of registering routes that are session aware and enabling Web API's to leverage Sitecore Anlaytics and Tracker.Current.
This video gives an overview of the feature and the implementation including an overview of how this module is leveraged by the Analytics feature, which includes a WebAPI for registering client side anlytics events.
Sitecore Foundation's API Foundation module provides helpers to register Web API routes and make them session and "Tracker" aware in Sitecore. Learn about them and how they are used in the Analytics API Controller.
I'll try to cover the Analytics feature in more depth in a future post as besides this controller we have plugins for segment.js analytics pub/sub model and out of the box tracking scripts for most of our foundation components.