Top 20 Backend Developer Interview Questions and Answers
Backend developers are responsible for creating and managing the server side of web applications. They use server-side programming languages and frameworks to develop, test and maintain the codebase that is responsible for the data storage, retrieval and communication between the server and the client-side. Here are the top 20 interview questions that will help you to hire the best candidates in the field:
1. What are the responsibilities of a backend developer?
A backend developer is responsible for writing and maintaining the server-side code of the application.
He/she ensures the proper functioning of the server, database and associated applications.
Backend developers work on the performance of the application, scalability and security.
2. What are the programming languages and frameworks you have worked in as a backend developer?
The answer to this question will depend on the candidate’s skills and experience. But, some of the commonly used programming languages and frameworks for backend development are Java, PHP, Python, Ruby, Node.js, and .NET.
3. What is the difference between server-side and client-side rendering?
Client-side rendering is the rendering of web pages on the client side using JavaScript. Server-side rendering is the rendering of web pages on the server side using server-side programming languages.
4. What do you understand by RESTful APIs?
RESTful APIs are the application programming interfaces that follow the REST (Representational State Transfer) architectural style. It uses HTTP request methods like GET, PUT, POST and DELETE, to interact with the server.
5. What is the difference between GET and POST methods?
GET is used to retrieve data from the server. POST is used to send data to the server.
6. What is the use of MVC architecture?
MVC (Model-View-Controller) is an architectural pattern used to separate the application into three components – Model, View, and Controller. It helps in separation of concerns, and maintains code quality and robustness of the application.
7. What is ORM (Object-relational Mapping)?
ORM is a programming technique that maps the objects of an application to the tables of a database. It helps simplify the data persistence operations and reduces the amount of boilerplate code needed to manage the database.
8. What is caching?
Caching is a technique used to store frequently accessed data in memory for faster access, reducing the number of queries to the database.
9. Explain the concept of Authentication and Authorization.
Authentication is the process of identifying the user by verifying the identity credentials such as username and password. Authorization is the process of determining whether the authenticated user has the required privileges to access a resource.
10. What is the difference between maintaining sessions using cookies and sessions using URL?
Sessions can be maintained using cookies or URL. Using cookies, the data is stored on the client-side and is more secure. On the other hand, using URL, the data is stored in the URL itself and is less secure.
11. What is SQL injection?
SQL injection is an attack in which an attacker tries to inject malicious SQL statements through the input fields of a web application. These statements can be executed by the database server, resulting in a breach of security.
12. What is the use of Database indexing?
Database indexing is a technique used to speed up the data retrieval process from the database. It creates a sorted data structure of values and stores it in memory, which helps to search and retrieve data much faster.
13. What is a Thread?
A thread is the smallest unit of execution in a computer program. It allows multiple tasks to run concurrently, sharing the same memory and resources.
14. What is the difference between Synchronous and Asynchronous calls in programming?
Synchronous calls wait for the server to respond before moving on to the next task. Asynchronous calls allow the server to respond in the future and let the program flow continue to execute without any wait-time.
15. What is the use of a version control system in development?
A version control system (VCS) is used to keep track of the changes made to a codebase over time. It allows developers to revert to previous versions of the code, work collaboratively, and coordinate changes within a team.
16. What is the process of deployment?
Deployment is the process of making the web application available for use by the public. It involves copying the code from the development environment to a production environment, configuring the server, and testing the application.
17. What is the difference between UDP and TCP?
UDP (User Datagram Protocol) is a connectionless protocol used for fast transmission of data, whereas TCP (Transmission Control Protocol) is a connection-oriented protocol that takes care of the reliability of the data transmission.
18. What do you understand by Content Delivery Network (CDN)?
CDN is a global network of servers that allows the web developers to distribute its content among the users from the nearest server location to improve user experience and performance.
19. How do you ensure the security of your application?
The security of an application can be ensured by various methods, such as encryption, using HTTPS and SSL, validating, and sanitizing the inputs, implementing access control measures, monitoring, and auditing.
20. What are the common debugging techniques for backend development?
The common debugging techniques for backend development are logging, error messages, break-point debugging, stack tracing, and unit testing.
These were the top 20 backend developer interview questions and answers that are essential for assessing the candidates' knowledge and experience. We hope that it will help you in choosing the best candidate for your organization.
How to Prepare for Backend Developer Interview
If you are aiming for a backend developer position, you must have a good knowledge of the technical aspects of software development. Along with the required technical skills, you need to be confident and articulate to impress the interviewer. Here are a few tips that can help you prepare for a backend developer interview.
1. Brush-up your technical skills
The first thing you need to do is brush-up on your technical skills. Backend development is all about programming languages, frameworks, and databases. Having a good knowledge of the desired programming language and frameworks will help you gain confidence during the interview. Ensure that you are updated with the latest frameworks and methodology to stay ahead in the competition.
2. Work on your Coding Skills
Ensure that you have a good grasp of data structures, algorithms, and the ability to write clean well-organized code. Practicing on coding platforms like HackerRank or Codewars can help you stay updated with the latest trends and sharpen your skills.
3. Get familiar with the company's product or services
Research the company you are going to interview with and its products or services. This will help you get an idea of what kind of backend system they have and the role you will be playing in it. Understanding the company's environment and culture will help you express your interest and suitability efficiently during the interview.
4. Be prepared to answer behavioral questions
Behavioral questions are designed to assess your problem-solving and communication skills. You can expect questions that evaluate your team-working, leadership, or conflict management skills. Additionally, they might ask you about a project you have worked on in the past that demonstrates your technical and analytical skills. Be prepared to answer these questions confidently.
5. Prepare questions to ask the interviewer
Asking questions during an interview is important, it will demonstrate your interest in the company and the role. Prepare a list of questions that can help you evaluate the company's environment, team dynamics, and your growth prospects within the company.
Following the above tips can help you have a successful backend developer interview. Remember to be confident, articulate, and show your passion for the job.
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