The Strat service should be served by any module in your environment that is running full active trading strategy. If you create and run standalone strategies, consider implementing this service yourself to leverage Dash and the other AWTS tools for visibility and management.
It provides functionality for interrogating the running strategy for status information, so that it can be visualized in Dash, or used to inform decisions in capital allocation.
Strategies implemented using Runner and the AWTS execution engine do NOT need to implement this API (use Stratworker instead). In this recommended scenario, Runner provides the management/reporting visibility for you.