API will secure application data from any unauthorised access to the portal. It use OAUTH token authorization mechanism and execute custom authorizer to help every incoming requests.
API Specification is much more concerned with the overall behavior of the Application. API are typically stateless and therefore easily scalable. Simultaneously run multiple versions of the same API, allowing to quickly iterate, test, and release new versions.
Different client applications (such as a desktop browser, Smart devices, mobile or Laptop) required different functionalities, thus introduced an API experience, with multi layer approach on top of existing API platform.