TOP 10 REST API interview questions with answers

REST API interview questions with answers: Here are some common REST API interview questions along with their answers: REST (Representational State Transfer) API is a type of web service that uses HTTP protocols to exchange data between client and server.

Table of Contents

RESTful APIs are designed to be stateless and rely on HTTP methods (such as GET, POST, PUT, DELETE) to interact with resources (such as data entities) identified by URLs (Uniform Resource Locators). REST APIs typically return data in JSON (JavaScript Object Notation) or XML (Extensible Markup Language) format, which can be easily processed by a variety of programming languages and platforms. REST APIs are widely used in web and mobile application development, as well as in integration and automation projects.

REST API Java Spring Boot

RESTful API development is a common use case for the Spring Boot framework. Here are the basic steps for building a RESTful API using Spring Boot in Java:

Set up a Spring Boot project: Use the Spring Initializr to create a new Spring Boot project with the necessary dependencies for building a RESTful API.
Define data model and database: Define the data entities and their relationships and choose a database technology (such as MySQL or PostgreSQL) to persist the data.
Implement controllers: Use Spring MVC annotations to define controller classes and methods that map to HTTP requests and implement the business logic for the API.
Define API endpoints: Define the API endpoints by mapping HTTP methods to specific URLs and specifying the parameters and response types.
Implement service layer: Implement a service layer to encapsulate the business logic and interact with the data layer.
Implement error handling: Handle errors and exceptions by defining exception handlers and using error responses with appropriate status codes.
Secure the API: Implement authentication and authorization mechanisms to protect the API from unauthorized access and attacks.
Test the API: Use tools such as Postman or Swagger to test the API endpoints and ensure that they are working as expected.
Deploy the API: Deploy the API to a web server or cloud platform (such as AWS or Azure) and monitor its performance and usage.

Spring Boot provides many features and libraries that make building RESTful APIs in Java easier and faster, including automatic configuration, dependency injection, and support for data serialization and deserialization.

REST API interview questions with answers

1. What is a RESTful API?

A RESTful API is an architectural style for building web services that uses HTTP methods (GET, POST, PUT, DELETE) to access and manipulate resources in a client-server architecture.

2. What are the main components of a RESTful API?

The main components of a RESTful API are resources (the entities being accessed), URIs (the addresses used to access the resources), HTTP methods (the actions performed on the resources), and representations (the format in which the resources are returned).

3. What is the difference between PUT and POST requests?

A PUT request updates an existing resource, while a POST request creates a new resource.

4. What is an HTTP status code, and what are some common status codes?

An HTTP status code is a three-digit code returned by the server to indicate the status of the request. Some common status codes include 200 OK (successful request), 404 Not Found (resource not found), and 500 Internal Server Error (server error).

5. What is the difference between authentication and authorization?

Authentication is the process of verifying the identity of a user or application, while authorization is the process of granting access to specific resources or actions based on the user’s identity and privileges.

6. What is a JSON Web Token (JWT)?

A JSON Web Token is a standard for representing claims securely between parties, typically used for authentication purposes. It consists of three parts: a header, a payload, and a signature.

7. What is HATEOAS, and how does it relate to RESTful APIs?

HATEOAS (Hypermedia as the Engine of Application State) is a constraint of RESTful APIs that requires a response to contain links to related resources, allowing the client to navigate through the API without prior knowledge of the server’s URLs or resource hierarchy.

8. What are some best practices for designing RESTful APIs?

Some best practices for designing RESTful APIs include using meaningful and consistent URIs, using HTTP methods correctly, returning appropriate status codes and error messages, using versioning to manage changes, and providing documentation and examples.

9. What are some common security concerns for RESTful APIs, and how can they be addressed?

Some common security concerns for RESTful APIs include authentication and authorization, data encryption, and preventing attacks such as SQL injection and cross-site scripting (XSS). They can be addressed by implementing secure authentication mechanisms, using encryption for sensitive data, and validating input data.

How can you test a RESTful API? RESTful APIs can be tested using tools such as Postman, cURL, or REST-assured. Testing can involve sending requests to the API endpoints and verifying the responses, testing error conditions, and performance testing.

API interview questions

Here are some common API interview questions:

What is an API?

API stands for Application Programming Interface. It is a set of protocols, routines, and tools used to build software applications.

What is the difference between a web service and an API?

A web service is a type of API that is accessed over the web using HTTP protocols. An API is a broader term that includes web services but can also refer to other types of interfaces, such as those used by operating systems or databases.

What are the different types of APIs?

There are several types of APIs, including RESTful APIs, SOAP APIs, RPC APIs, and GraphQL APIs.

What is the difference between a RESTful API and a SOAP API?

RESTful APIs are based on the HTTP protocol and use simple URL-based requests and responses to interact with resources. SOAP APIs, on the other hand, use XML-based messages sent over a variety of protocols and can be more complex to implement and use.

What is an HTTP method, and what are some common methods used in RESTful APIs?

HTTP methods are used to indicate the action being performed on a resource. Some common methods used in RESTful APIs include GET (retrieve a resource), POST (create a new resource), PUT (update an existing resource), and DELETE (delete a resource).

What is an API endpoint?

An API endpoint is a URL that specifies the location of a resource or service being accessed through an API.

What is versioning in an API, and why is it important?

Versioning refers to the practice of assigning a version number to an API to indicate changes or updates made to the interface. It is important to avoid breaking changes and maintain backward compatibility.

What is authentication, and why is it important in an API?

Authentication is the process of verifying the identity of a user or application. It is important in an API to ensure that only authorized users or applications can access resources or services.

What are some best practices for designing an API?

Some best practices for designing an API include using consistent and meaningful resource names and URLs, using HTTP methods correctly, providing clear and concise documentation, and designing for scalability and flexibility.

What are some common challenges when building or using an API? Some common challenges when building or using an API include managing versioning and backward compatibility, ensuring security and privacy, handling errors and exceptions, and optimizing performance and scalability.

Java Interview Questions With Answers

Join Telegram	Join Now
Home Page	Full Stack With Java