REST API’s: What are they and what do they do?

Have you ever wondered how your favorite apps and websites are able to gather information from various sources? The answer lies in the use of REST APIs, or Representational State Transfer Application Programming Interfaces. In this blog post, we’ll explore how REST APIs work and how they facilitate communication between different applications.

At a high level, a REST API allows one application to interact with another by sending and receiving data over the internet. This data is sent using the HTTP protocol, which is the same protocol used by web browsers to request and receive web pages. When an application sends a request to a REST API, it is essentially asking the API to perform an action or provide some information.

Let’s take a closer look at the individual components that make up a REST API:


The first component of a REST API is resources. A resource is a piece of data that an application can request or modify using the API. For example, a resource could be a customer record, a product listing, or a weather forecast.


Each resource in a REST API is identified by a unique URI, or Uniform Resource Identifier. This URI is used to indicate which resource an application is requesting or modifying. For example, the URI “/customers/123” might be used to request information about customer 123.


REST APIs support several HTTP methods that are used to interact with resources. The most common methods are:

GET: Retrieves a resource

POST: Creates a new resource

PUT: Updates an existing resource

DELETE: Deletes a resource


When an application requests a resource from a REST API, the API returns a representation of that resource. This representation can take many forms, such as XML, JSON, or plain text. The application can then use this representation to display the resource or modify it as necessary.

Status Codes

Finally, REST APIs use HTTP status codes to indicate the result of a request. These codes indicate whether the request was successful or encountered an error, and can provide additional information about the nature of the error.

So how does all of this come together to facilitate communication between applications? Let’s walk through an example scenario:

Suppose you are using a weather app on your phone that uses a REST API to retrieve weather data. When you open the app, it sends a request to the API using the GET method and a URI that identifies the location for which you want weather data. The API then retrieves the requested data and returns it to the app in a representation format, such as JSON. The app can then use this data to display the current weather conditions for your location.

REST APIs are a powerful tool for enabling communication between applications. By providing a standard set of resources, URIs, methods, representations, and status codes, REST APIs make it possible for different applications to interact with each other seamlessly. Whether you’re building a new app or integrating existing systems, understanding how REST APIs work is essential for making your application work with others on the internet.

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