To build tomorrow’s applications we use yesterday’s technologies: this can be clearly seen in the world of mobile applications. The traditional architecture that worked well for Web applications was not effective anymore, so the technological world came up with a new solution: the central bus for integration or an ESB.
But the technological world kept developing and changing. Currently companies prefer non-monolithic solutions and have developed numerous applications both on-premise and in the cloud to meet their business needs. There are also a huge number of lightweight APIs distributed everywhere and being constantly consumed by other applications of every type. In this complex modern scenario, it is almost impossible to fully utilize an ESB to its full capacity, hence the importance of an API Server witch is able to manage all the internal services needed (just like an ESB) but is also able to operate on a cloud level.