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Exploring REST API: Definition, Benefits, and Key Features

Learn the fundamentals of REST API in this beginner's guide. Discover how it works, its benefits, and best practices for using it in your web application.

Written by RamotionApr 7, 202316 min read

Last updated: Feb 16, 2024

REST API has been making waves in the web application development services industry these days, with more and more companies moving towards it. It is an ideal model for building scalable web applications, thanks to its uniform representation of resources across the web. In this beginner's guide, you will learn everything you need to know about REST API, including its benefits, uses, and a basic introduction to using it with Node.js.

REST API is one of the most popular approaches for building web APIs. It describes a set of rules for standardizing programming languages and text using JSON (JavaScript Object Notation), HTML, or XML. The REST API is a specification that defines how RESTful web services should be built and consumed. It’s the industry standard for building APIs on top of HTTP (Hypertext Transfer Protocol), which is what powers the web.

The REST API allows developers to create applications that can interact with a web service. It’s easy to use, because it provides a standard way of interacting with data, which means it’s easy to learn and implement.

Definition of REST API

REST stands for REpresentational State Transfer. REST APIs follow a set of principles designed to help developers create scalable, secure and maintainable software systems. REST is an architectural style that uses HTTP REST API methods (GET, POST, PUT and DELETE) to create a uniform interface for accessing data over the Internet. A RESTful API will use these HTTP methods to expose CRUD operations in a way that allows developers to easily use them.

Importance of understanding REST API

  • REST APIs are becoming increasingly important as more and more applications are built on top of them. They can be used to expose backend data to mobile apps, websites or even IoT devices. Many companies use RESTful APIs to create a software development kit (SDK) that allows developers to build applications using the company’s technology without having to host their own servers.
  • REST APIs are also used by companies that have a large amount of data to share with developers, but don’t want their data sitting in the hands of third parties. For example, many social media platforms offer REST APIs so that programmers can build applications around their data without having to host the application themselves.
  • REST APIs are designed in a way that allows developers to query and manipulate data without requiring them to know how the data is stored on the server. This allows programmers with little or no experience in SQL or database management systems (DBMS) to create applications quickly. However, it also means that companies need to ensure that their APIs are well-documented and easy for developers to use.

Benefits of REST APIs

REST APIs are a popular choice for web and mobile application developers because they are easy to use, offer a great amount of flexibility, and are well supported by many programming languages and frameworks. There are several benefits to using REST APIs:

Flexibility and scalability

REST APIs are flexible and scalable, which makes them ideal for building apps that can grow with your business. You can use REST APIs to create a new feature or to add an additional module to an existing application.

This is because you can use the same API to create a new application or feature. This means you only have to maintain a single source of truth for your data, which reduces costs and makes it easier to develop new features.

REST APIs are flexible because they can be used with any programming language, framework or device. They also offer a high level of scalability and are easy to manage by simply adding more servers if the load increases.

Low coupling and high cohesion

REST APIs are implemented in a highly decoupled way, meaning that they're easy to modify and extend. When you add a new feature or fix an existing one, it won't change anything else in the application.

Highly cohesive means that the components of an application are highly related to each other. This makes it easier to understand how everything works and where changes need to be made. Highly cohesive REST APIs have a clear separation of concerns. This makes it easier to understand how everything works and where changes need to be made. It also makes it more obvious where new features can be added without breaking existing code.

Easy to understand and implement:

There are many ways to implement RESTful APIs. They can be implemented using a wide variety of programming languages and frameworks, each with their own strengths and weaknesses. This gives you the flexibility to choose what works best for your organisation’s needs.

It’s important to remember that while it’s easy to implement a REST API, it’s not always easy to maintain. A poorly designed REST API can quickly become an unmanageable mess. This is why it’s so important to get things right from the beginning by following best practices and using tools like Swagger, which helps you create clean, readable documentation for your API.

Stateless architecture

Stateless architecture is an architectural style where each request from a client is independent from every other request. This means that the server doesn’t store any data about a given user between multiple requests and only processes each one independently. Stateless applications are much easier to scale because they don’t require any specific configuration or code changes when adding more servers to handle more traffic.

This is an important distinction between stateless and other styles of application architecture, which may rely on storing data in memory or in a database. This means that you don’t have to worry about scaling your application horizontally or vertically but instead can focus on improving performance through caching and content delivery networks (CDNs).

How does RESTful APIs work

The key REST principles include the use of a uniform interface, stateless communication, caching, and layered system architecture. These principles ensure that the API is scalable, flexible, and easy to maintain.

Client-server architecture

RESTful APIs use the client-server communication model, in which the API acts as a server and the client program acts as a client. The client sends requests to the API, which returns responses. These requests and responses are formatted in a specific way so that both sides can understand each other. The API uses HTTP methods (GET, POST, PUT, DELETE), status codes (200 OK), and request headers (Accept: application/json).


HTTP methods represent the various ways in which clients can send requests to APIs. Each method has a specific purpose, and the API developer defines these methods when designing an API. GET is used for access resources from a server (i.e., reading data). POST is used for creating new resources on the server, such as adding new users or creating products. PUT is used for updating existing resources on the server (i.e., editing data). DELETE is used for deleting resources from a server.

There are several other HTTP methods, but these are the most common and widely used.

Uniform Resource Identifiers (URI)

A URI is a string of characters that identifies a resource. It typically takes the form of a URL and can include parameters that specify how the resource should be accessed. are used to identify resources. A URI is composed of three parts: the scheme, the authority, and a path. The scheme identifies how to interpret any information that follows it; it’s often “http” or “https” (for secure connections). The authority identifies which server to connect to; this can be a domain name or IP address. Finally, the path indicates what resource you want from that server.

Representation of resources (JSON, XML)

Resource representations are the structures used to encode and transmit resources over HTTP. The most widely-used representation is JSON, but XML can also be used. Both formats allow you to define a structure for data that’s easier for humans to read than the raw bytes of binary data.

In JSON, each value is represented by a key-value pair. The keys are strings of characters separated by colons (:), and the values can be any type of data except a string or number. In XML, you use tags to define your structure; every tag starts with an opening angle bracket (<) and ends with a closing one (>).

REST API Requests

REST API requests are the methods that your application uses to send information to a REST API. A REST API request is an HTTP request with a method (such as GET, POST, PUT, and DELETE), an endpoint URL, and a payload of data or a body that contains information about the request. The payload may be encoded in various formats, depending on the application.

HTTP Request Methods

There are several different HTTP request methods, which are used to specify how the client wants to interact with a web server. The most common HTTP request methods include GET, POST, PUT, and DELETE.


The GET request method is used for retrieving resources from the web server. This method is generally used for reading information from a REST API, as opposed to sending data. It should not be used to send data unless it’s encoded into the URL itself.


The POST method is used to send data to the web server. This request method is most commonly used when uploading files or submitting forms. When using this request method, the client sends data in the body of the HTTP message.


The PUT request method is used to update resources on the web server. This method is most commonly used for updating data in a REST API, such as updating a blog post or changing the status of an order. The client sends data in the body of the HTTP message.


The DELETE request method is used to delete resources on the web server. This request method is most commonly used for deleting data from a REST API, such as removing an order from an online store’s database.

URI structure and parameters

A URI is a unique identifier for a resource on the web server. This identifier can be used to make requests to that resource. The URI structure of a REST API is very important. The format of the URI should be consistent across all resources in order to help clients determine which HTTP request method to use. For example, if your URL is example. com/products?page=1&perpage=10&sortby=price then you can assume that GET requests are used to retrieve data from this resource, while POST requests are used to create new products.

Headers and body

The headers and body of the HTTP request contain all of the information necessary to make a request. The headers are key-value pairs, while the body contains any data that is required by your API to process a request. If you want to retrieve resources from an API, you need to include all of the required parameters in your HTTP request.

These parameters will vary depending on what kind of resource you are accessing (e.g., products or orders) as well as whether it's an insert/update or read-only operation.

REST API Authentication Methods

REST API authentication is the process of verifying a user's identity. This can be accomplished by using an API key or API token, or by providing some other information (such as a username and password) that can be used to identify the user.

Basic Authentication

Basic authentication uses a username and password to authenticate users. The "basic" part refers to the fact that this method uses the HTTP Basic Authentication standard, which is defined in RFC 2617.

Token-based Authentication

Token-based authentication uses an access token instead of credentials (username/password) to authenticate api consumers. The token may be a JSON Web Token (JWT) or an Authorization header containing an access token.

OAuth2 Authentication

OAuth 2 is an open authorization standard that allows users to grant permission to an application for specific resources or operations on their behalf without sharing their credentials (username/password). The OAuth 2 framework includes specifications for two types of tokens: access tokens and refresh tokens. An access token is a string that represents a user’s authorization, whereas a refresh token is used to obtain new access tokens when they expire (or in some cases can be used as part of an authorization request).

Principles of REST API

REST APIs are the basis of most modern web applications. They provide a simple, standard way for applications to access and modify data on a website.

Here are the core principles of REST API:

Priority of Business Needs

The most important principle of REST APIs is that they should always be designed to meet the needs of the business and not just developers. The API needs to provide only the client functionality required by the application and nothing more. REST APIs should be designed around the needs of the business, not as an afterthought.

The API itself should not be designed to support a specific technology or application: instead, it should provide a data model that allows all types of applications to interact with each other in a standard way.

Stateless Architecture

The REST architecture is designed to be stateless. This means that each client request results in a new response from the actual server, with no knowledge of previous client requests or responses. This approach makes it easier for systems to scale and provides better performance because each client doesn’t have to store its own context information about past interactions with the server.


The REST architecture is designed to be cacheable. This means that each response from the server can include expiration information, so clients can cache a copy of the response and use it in future client requests. This helps reduce the load on the server because fewer requests are made overall, and also allows clients to perform certain types of processing locally instead of sending all data back to the server for processing.

Layered System

The REST architecture is designed to support a layered system. This means that the server can provide APIs (application programming interfaces) for client applications to use, which allows clients to access only the functionality they need. This helps reduce the amount of code that needs to be written by developers and makes it easier for new features to be added in the future.

How to Use a REST API

The first step to using a REST API is to choose a programming language. You can use any language that supports HTTP requests, but some languages are more popular than others. If you’re not sure which one to use, start with the most popular option: JavaScript. The most popular programming language in the world, JavaScript is also the easiest one to learn.

Using HTTP libraries

There are dozens of frameworks and libraries that make it easy to work with REST APIs, so you’re unlikely to run into any compatibility issues. If you already know a little bit about JavaScript, learning how to use a REST API should be straightforward.

You can find tons of resources online that provide a basic introduction to REST APIs and how to use them with JavaScript. If you’re already familiar with the basics of HTTP requests and responses, it shouldn’t take long before you can start building your own applications.

Handling errors and exceptions

When you’re working with REST APIs, it’s important to be prepared for errors and exceptions. When the server returns an error response, you should handle it by displaying a message to the user. For example, if your request fails because of a missing parameter or invalid data format, then your application should display an error message explaining what went wrong.

There are two main ways to handle errors and exceptions when you’re working with REST APIs:

1) Return HTTP status codes

You can use the standard HTTP response codes to indicate success or failure. For example, if your request was successful, the server might respond with a 2xx status code; if not, it might return a 4xx or 5xx status code. This approach is very straightforward but doesn’t provide much context about what went wrong.

2) Return JSON payloads with error information

You can use the standard HTTP response codes to indicate success or failure, but also return a JSON object that includes more detailed information about what went wrong.

Creating a REST API

REST Compared to Other API Paradigms


REST is an architectural style for building software applications. The REST architectural style defines a set of constraints to be used for designing distributed systems. These constraints include using a uniform interface and applying the principle of statelessness, which is one of the biggest advantages of using REST APIs over SOAP APIs.

REST APIs are based on HTTP requests (GET, POST, PUT, DELETE), which can be easily understood by humans as well as computers. This makes them more robust and easier to implement than SOAP APIs.

SOAP is a protocol that defines how information is passed between two programs in a message format with defined beginning and end points. SOAP uses XML to define messages and encodes response data with XML schemas. SOAP was designed as an alternative to other messaging protocols like Simple Object Access Protocol (SOAP) or Remote Procedure Call (RPC). But SOAP has limitations such as being verbose and not supporting streaming or partial responses from servers.

REST vs. GraphQL

REST is a software architecture style for developing RESTful web services. It stands for Representational State Transfer and was introduced by Roy Fielding in his PhD dissertation. It's a simple, stateless, and cacheable communication protocol that lets you transfer data over HTTP.

GraphQL is a query language developed by Facebook to query databases. It uses the same principles as REST but provides an alternative approach to querying data over HTTP requests.

GraphQL is a query language for APIs, and it has a syntax that looks like JSON but with some differences. It’s based on the idea of building queries that can be run against any API endpoint and returning only the data that you need.


In conclusion, we have explored the main points of REST API, including its definition and key features. We have also highlighted the importance of using REST API in modern applications, such as scalability, flexibility, and ease of integration. As technology continues to advance, REST API will continue to play a vital role in building robust and efficient software systems.

It's important to use REST API in modern applications because it provides a standard and consistent approach to building RESTful web services, making it easier for developers to collaborate and integrate different systems. It also enables the development of loosely coupled services, which can be more easily maintained and updated over time. Overall, REST API is an essential tool for creating modern, scalable, and interoperable web applications.