Each Reliable Actor service you write is a partitioned and stateful Reliable Service. Service Fabric API provides a asynchronous and single-threaded programming model to implement Actors. You only need to work on the Actor implementation, the platform takes care of lifecycle, upgrades, scale, activation, and so on.

Actors closely resemble objects in object-oriented programming. Similar to the way a .NET object is an instance of a .NET type, every Actor is defined as an instance of an Actor type. For example, there may be an Actor type that implements the functionality of a sensor monitor and there could be many Actors of that type that are distributed on various nodes across a cluster. Each such Actor is uniquely identified by an Actor ID. Repeated calls to the same Actor ID are routed to the same Actor instance. For this reason, Actor services are always stateful services.