Hi venkatesh , 

what is api ?

API is the acronym for Application Programming Interface, which is a software intermediary that allows two applications to talk to each other. 

Each time you use an app like Facebook, send an instant message, or check the weather on your phone, you’re using an API. 

API lets a developer make a specific “call” or “request” in order to send or receive information. This communication is done using a programming language called “JSON.”  It can also be used to make a defined action such as updating or deleting data. There are four basic request methods that can be made with API:

1. GET – Gathers information 
2. PUT –  Updates pieces of data 
3. POST – Creates
4. DELETE – Deleting 

What about REST & SOAP APIs?

While API follows a specific set of rules that determine how programs communicate with one another. REST & SOAP define how the API is presented. Each are similar in functionality but have several key differences and use cases. 

REST stands for “Representational State Transfer” and is the set of rules that developers follow when creating an API. REST is read using JSON as we covered previously. One of these rules is that the API should be designed in a way that is easy to use and will make sense for developers. An example of not following this rule would be to have the product endpoint “prod_839” instead of just “products.” As this could cause the API to be fairly unpleasant to work with. 

SOAP or Simple Object Access Protocol is another design modal for web services. Instead of the typical JSON that REST API uses. SOAP uses a language known as Extensible Markup Language (XML). XML is designed to be machine- and human-readable. SOAP follows a strong standard of rules, such as messaging structure and convention for providing request or responses. 

Advantages of using APIs for developers:

1. Automation: with APIs, computers rather than people can manage the work. Through APIs, agencies can update work flows to make them quicker and more productive.
2. Application: because APIs can access the app components, the delivery of services and information is more flexible.
3. More scope: with an API an application layer can be created which can be used to distribute information and services to new audiences which can be personalized to create custom user experiences.
4. New data available: an API allows all of the information generated at the government level to be available to every citizen, not just a select few.
5. Efficiency: when access is provided to an API, the content generated can be published automatically and is available for every channel. It allows it to be shared and distributed more easily.