Application Programming Interface (API)

• API is application programming interface which consist of interfaces, helper class and implementation classes.
• API is used for inter application communication. It means one application can communicate with another application by using API.
• The backbone of API is abstraction.
• Advantage of API is loose coupling.
• If API is developed in java lang then it will be given in the form .jar file.
• First form of API is consist of interface, helper classes and implementation classes.
• First form of API is exposed to the developer to write the business logic.

• Second form of API consist of interfaces and helper classes.
• implementation classes separated into drivers.
• Second form of API is exposed to the developer to write the business logic.
• It is also exposed to the vendor to provide the implementation classes.