In a microservice architecture, which component is NOT typically part of the call chain?

In a microservice architecture, a data storage service is generally not part of the call chain that occurs during service-to-service communication. The call chain typically consists of components that interact directly with one another to fulfill a specific request. This involves services such as the authentication service, which verifies user credentials; the billing service, which processes payment transactions; and a load balancer, which distributes incoming requests to ensure that no single service instance is overwhelmed.

Data storage services are often abstracted away from the direct communication flow between microservices. Instead, they are accessed via operations (like CRUD operations) that are invoked by the services in the call chain when they need to retrieve or store data. Therefore, while data storage is crucial in the overall architecture, it does not participate in the immediate call chain as a direct communication component between microservices.