Features of Kotlin: Expressiveness: It uses features like type-safe builders and delegated properties which uses the concept of abstraction. Scalability: It allows a developer to develop such applications which can support a large number of user with modest hardware requirements. Interoperability: Kotlin can be used with java based frameworks. Migration: A old system written in java can be converted into kotlin based system.

When you are making an API you are opening a door to the world. As we know the world is full of good and bad people, so we need to secure our data from bad guys. So we need to add multilayer security. Simple Security