What are APIs ? How they Work ?

APIs, or Application Programming Interfaces, allow different software applications to communicate and share information with each other. They act as a bridge, enabling applications to work together seamlessly.

So how do APIs work? Imagine two islands, Island A and Island B, separated by a river. If a person living on Island A wants to share some information with their friend on Island B, there are several ways to connect with them:

• Using a phone

• Using a boat

• Using a bridge

All of these methods help the person on Island A to connect with their friend on Island B. In the same way, APIs facilitate communication between applications. Island A represents the client application that makes a request to the server application on Island B. The server application processes the request and generates a response, which is sent back to the client.

In this way, APIs enable different applications to interact with each other in a standardized way, making it possible for them to share data and work together seamlessly.

Ingredients of an API

Here are the basic ingredients you need to make an API request:

1. Endpoint URL:

   This is the URL or web address of the API endpoint that you want to access. It specifies the location of the resource or service you want to interact with.

2. HTTP Method :

   This refers to the type of request you want to make to the API endpoint, such as GET, POST, PUT, or DELETE. Each method has a specific purpose, such as -GET -----> retrieving data

   POST --> creating new data

   PUT -----> updating data

   DELETE ----> deleting data

3. Query Parameters :

   These are optional parameters that you can include in the endpoint URL to customize the data returned by the API. Query parameters can be used to filter, sort, or paginate data.

4. Request Body:

   This is optional data that can be included in the request body for methods like POST or PUT. The request body typically contains data in a specific format such as JSON or XML, which is used to create or update resources on the server.

Example

This is an example of an HTTP POST request sent to the /api/books endpoint of an API hosted at api.example.com. The request body is in JSON format and includes data for a new book, including the book's title, author, ISBN, and published year. The Content-Type header is set to application/json to indicate that the payload is in JSON format. This request is used to add a new book to the API's database.

POST /api/books HTTP/1.1

Host: api.example.com

Content-Type: application/json

{

"title": "The Hitchhiker's Guide to the Galaxy",

"author": "Douglas Adams",

"isbn": "9780345391803",

"published_year": 1979

}

We learned that APIs allow different applications to communicate and share information with each other. APIs facilitate communication between client and server applications using standardized methods like HTTP methods (GET, POST, PUT, DELETE) and query parameters. APIs are essential for creating interconnected systems that work seamlessly. We also saw an example of a POST request used to add a new book to an API's database.