AKA the BLL or Business Logic Layer? I guess the only reason you would re-write business logic in the presentation layer is because you can&#x27;t afford the extra round-trips, and it&#x27;s cheaper than writing an aggregation layer on your backend.<p>But generally wouldn&#x27;t you just add the APIs into the core microservice to return the requested dataset (at the various necessary &quot;levels&quot; of cardinality) for the various different consumers? Keeps everything in one place.<p>Then you use nginx lua script to allow a single HTTP request from the client to be dispatched to the various microservices and packaged together in the reply in a singel round-trip. This can be just a few lines of code serving any combination of possible sub-requests. I don&#x27;t like the idea at all of building another service layer on the backend to do the aggregation and expose a different API... I think you can do something similar in the development branch of HAProxy.