Understanding What is REST API?

Have you ever wondered how different software applications manage to communicate over the internet smoothly and efficiently? A REST API is a protocol that uses standard HTTP methods like GET and POST to allow for such interaction, treating data and functionality as resources that can be accessed and manipulated using the web's existing infrastructure. Let's understand more!

A REST API (Representational State Transfer Application Programming Interface) is an architectural approach to designing web services that interact with systems using HTTP to make calls for data and services. It utilizes the existing technology and protocols of the web, including HTTP itself, and is designed around the concept of treating all server-side objects as resources that can be created, retrieved, updated, or deleted using the corresponding HTTP methods. In this blog, we will learn about REST API in detail!

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Table of Content

• What is an API?
• What is REST?
• What is REST API?
• Core Principles of REST
• Components of a RESTful System
• Advantages of REST APIs
• Best Practices in REST API Design

What is an API?

An API (Application Programming Interface) is a set of rules and protocols for building and interacting with software applications. APIs define the methods and data formats that developers can use to interact with the program, perform requests, and receive responses. APIs act as an intermediary layer that allows different software systems to communicate with each other.

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What is REST?

REST or Representational State Transfer is an architectural style for designing networked applications. It relies on a stateless, client-server, cacheable communications protocol, the standard being HTTP. REST is often used in the development of web services due to its simplicity and how it effectively uses HTTP methods to match the operations they perform, which makes it a popular choice for building APIs.

What is REST API?

A REST API (Representational State Transfer API) is a set of web standards used to manage the interactions between client and server applications via the internet. It allows systems to communicate over HTTP in a simple and standardized way, making it an ideal method for building web services and applications.

Core Principles of REST

1. Client-Server Architecture

The client and the server must be independent of each other. This separation allows for the components to evolve independently, enhances the portability of the user interface across multiple platforms, and scales the server components without affecting the client.

2. Statelessness

Each request from a client to a server must contain all the information needed to understand and complete the request. The server should not store any session information about the client. This makes REST services simpler and more scalable.

3. Cacheability

Data within a response needs to be implicitly or explicitly labelled as cacheable or non-cacheable. If a response is cacheable, then a client cache is given the right to reuse that response data for later, equivalent requests. This helps improve the efficiency and performance of applications.

4. Uniform Interface

This principle is fundamental to the design of any RESTful system. It simplifies and decouples the architecture, which enables each part to evolve independently. The uniform interface includes using standard HTTP verbs (GET, POST, PUT, DELETE, etc.), standard HTTP error responses, and resource identification through URI.

5. Layered System

A client cannot ordinarily tell whether it is connected directly to the end server or to an intermediary along the way. Intermediary servers can improve system scalability by enabling load balancing and providing shared caches. Layers also enforce security policies.

6. Code on Demand (optional)

Servers can temporarily extend or customize the functionality of a client by transferring executable code. This is the only optional constraint of REST, and it can be used to send code from the server to be executed on the client (e.g. JavaScript).

Components of a RESTful System

A RESTful system refers to a system that adheres to the principles of REST (Representational State Transfer), an architectural style designed for network-based software architectures, particularly the web. REST was introduced by Roy Fielding in his doctoral dissertation in 2000, and it has since become the standard way to design networked applications, especially those involving web services and APIs.

Advantages of REST APIs

Best Practices in REST API Design

• Name API endpoints with nouns representing entities, not actions (e.g. /users).

• Apply HTTP methods consistently: GET (retrieve), POST (create), PUT (replace), PATCH (update), DELETE (remove).

• Employ common HTTP responses like 200 OK, 404 Not Found, and 500 Internal Server Error to communicate outcomes.

• Adopt clear and predictable naming conventions for easy understanding of API functionality.

• Version your API (e.g. /api/v1/) to manage changes without affecting existing users.

• Allow filtering, sorting, and pagination through explicit query parameters.

• Design lightweight request and response payloads to improve performance.

• Implement security measures like HTTPS, OAuth, and input sanitation to protect your API.

• Offer comprehensive, clear API documentation to facilitate easy integration and usage by developers.

• Ensure each API call contains all necessary information, making the API scalable and reliable.

Thus, REST APIs are fundamental in assisting communication between different software systems, particularly in the creation of web and mobile applications, where they provide a clear and efficient way to interact with backend systems.