Intent

The user makes a single call to the Aggregator, and the aggregator then calls each relevant microservice and collects the data, apply business logic to it, and further publish is as a REST Endpoint. More variations of the aggregator are:

Proxy Microservice Design Pattern: A different microservice is called upon the business need.
Chained Microservice Design Pattern: In this case each microservice is dependent/ chained to a series of other microservices.

Applicability

Use the Aggregator Microservices pattern when you need a unified API for various microservices, regardless the client device.

Credits

Microservice Design Patterns