A stateless service treats each request as a separate transaction that is independent of any previous request sent to the service. This service can not maintain an internal session store. A stateless service takes all the parameters that it needs to perform an operation at once.
However, you would rarely find applications that are truly stateless. In most of the scenarios, you would find that the state is externalized and stored separately. For instance, a service might use Azure Redis Cache to store state data and not maintain state internally.
Most of the stateless services built on Service Fabric are frontend services that expose the functionality of the underlying system. Users interact with the frontend services, which then forward the call to the correct partition of appropriate stateful services.
