With the increasingly collaborative scenarios in which APIs are used, as well as the growing maturity and scale of microservice architectures, the idea of API coordination has become a hot topic.
Sam Newman and Phil Calçado have popularized the “Back-end for Frontend (BFF)” deployment pattern, which describes a topological approach to coordinating service API calls. However, coordinating API calls in a distributed software system is not a new problem. It has been a concern even from the early days of SOA. In my experience, software architects can often conflate the different types of coordination when trying to determine function placement in their application integration efforts. To help address this pitfall, here is a classification system I use: