In the beginning (that is, the 90’s), developers created the three-tier application. Per Martin Fowler, these tiers were the data source tier, managing persistent data, the domain tier, implementing the application’s primary business logic, and the presentation tier, handling the interaction between the user and the software. The motivation for this separation is as relevant today as it was then: to improve modularity and allow different components of the system to be developed relatively indepe...