Top 10 Interview Questions for Backend Dev

Top 10 Interview Questions for Backend Dev

Interviews feel overwhelming? It’s just your nerves making them seem daunting. This blog shows you how to conquer your interview fears. Read on to shoo away the stress and ace your next interview!

No matter how proficient you are in a particular skill, how much experience you have or how well-acquainted you are with your core concepts, appearing for interviews can always be nerve-wracking. Acing interviews requires a distinct skill, set apart from your technical knowledge. Of course, having a strong grasp of the relevant skills, along with pertinent projects and work experience is crucial. However, the most important aspect of any interview is your ability to effectively communicate your expertise and experiences. In many cases, your ability to present yourself and your work convincingly can be more critical than your technical skills.

In this blog, we will explore strategies to excel in interviews, discuss some of the most asked interview questions and increase your chances of securing that job, college admission or project with smart preparation. Let’s dive right in.

Introduction

Interviews can be challenging primarily because we often focus on the wrong aspects during preparation, leading to mistakes during the actual interview. Another reason interviews are difficult is their unpredictability- interviewers can ask anything within the domain, which can easily trigger anxiety.

However, interviews aren't as daunting as they seem. Understanding what your interviewer expects and preparing accordingly, often just one step ahead, can significantly set you apart from the competition.

For most entry-level and intermediate positions, interviewers don’t expect you to know everything about the subject. Instead, they look for a solid understanding of the basics and your ability to communicate clearly. A common mistake candidates make is focusing too much on complex concepts while neglecting simpler, fundamental ones. Below are some of the most common interview questions along with tips on how to answer them effectively. The best way to utilize this blog is to read each question and attempt to answer it yourself before checking the provided answers. You might find that while you can recall many concepts, explaining them clearly can be challenging.

Here is a list of the top 10 most frequently asked Node.JS questions in interviews-

  1. What is Node.js?

Yes, this is a basic question, but it's often where candidates stumble. While you might know what Node.js is, explaining it succinctly can be tricky because it’s so foundational and frequently referenced.

Tips to answer this question:

  • Make sure to mention that Node.js is a runtime environment. It’s not a programming language, framework, or tool. 

  • Node.js is widely used for backend development, especially for building scalable applications. 

  • Be sure to include key terms like “runtime environment,” “backend development,” and “scalable” in your answer. Be prepared to elaborate on these keywords if asked.


  1. How is Node.js a runtime environment on the server side? (Follow-up question: What is V8?)

Mentioning specific terms in an interview can be a double-edged sword. It shows that you know your stuff but also invites follow-up questions.

Tips to answer this question:

  • Keep it short and simple. Use simpler words to define this.

  • If we take the Chrome Browser, it uses V8 as the JavaScript engine to run in the browser for the client side. Now using Node.js this code can be used outside the browser as well on the server side.

  • V8 is the JavaScript engine inside the Chrome Browser. 

  • There might be follow up questions regarding the JavaScript engine in other browsers. Be prepared for such questions.

(Hints to the follow up- V8 is the JavaScript engine in the Chrome browser, and Node.js leverages it to run JavaScript code on the server. Be ready to discuss other JavaScript engines used in different browsers if prompted.)


  1. What is the difference between a framework and a runtime environment? (Can be asked as a follow-up question as well)

This is another fundamental question that often trips up even seasoned developers. The difference might seem subtle, but it’s crucial to understand.

Tips to answer this question:

  • A framework is a collection of pre-written code that helps you structure and develop your application more efficiently.

  • Provide some well known examples of frameworks.

  • Define runtime environment- A runtime environment provides the infrastructure for your code to run. It doesn't dictate how your code should be structured but instead focuses on executing it. 

  • Provide some well known examples of Runtime Environments.


  1. What is Express.js, and how is it different from Node.js?

Express.js is a key player in the Node.js ecosystem and is often brought up in interviews.

Tips to answer this question:

  • Define Express.js in simple terms- Express.js is a web application framework built on top of Node.js. It simplifies the process of building web applications and APIs by providing a robust set of features such as routing, middleware, and template engines.

  • Explain the main differences asked in the question- Node.js, as mentioned earlier, is the runtime environment that allows JavaScript to run on the server. Express.js is used to build applications on top of this environment.

  • Make sure to emphasize that Express.js extends Node.js functionalities and is designed specifically for building server-side applications.


  1. What is the difference between Client-side (Browser) and Server-side (Node.js)?

Understanding the distinction between client-side and server-side is fundamental, especially when working with full-stack technologies.

Tips to answer this question:

  • Define the two in simple terms- The client-side refers to everything that happens in the user’s browser. It’s responsible for rendering the user interface and handling user interactions. The server-side refers to operations that happen on the server, where the application’s logic is executed. Node.js handles tasks like processing requests, accessing databases, and managing server resources.

  • When explaining this, you might want to give examples of what kind of code runs on each side to make it more relatable.


  1. What is Single-threaded, and is Node.js single-threaded?

This question dives deeper into the workings of Node.js and can catch you off guard if you're not well-prepared.

Tips to answer this question:

  • Define the two in simple terms- Node.js is indeed single-threaded, meaning it processes one command at a time on a single thread.

  • Be prepared to explain how Node.js handles concurrency despite being single-threaded.


  1. What is package.json in Node.js?

A common question that delves into the practical aspects of working with Node.js projects.

Tips to answer this question:

  • You know the drill, give a simple definition- The package.json file serves several purposes (enlist all its purposes)

  • Make sure to mention that understanding package.json is crucial for maintaining and scaling Node.js applications.


  1. What is Middleware in Express.js?

Middleware is a core concept in Express.js, and understanding it is essential for building robust web applications.

Tips to answer this question:

  • Definition- Middleware functions in Express.js are functions that have access to the request and response objects and can modify them. They are used for tasks like logging, authentication, error handling, etc.

  • Can enhance this answer by giving an example of a simple logging middleware that logs every request made to the server.


  1. What is the Event Loop in Node.js?

Understanding the Event Loop is key to grasping how Node.js handles asynchronous operations.

Tips to answer this question:

  • Definition- The Event Loop is the mechanism in Node.js that allows it to perform non-blocking I/O operations, despite being single-threaded.

  • You might want to explain how the Event Loop works in conjunction with the callback functions to manage asynchronous tasks without blocking the execution of other code.


  1. How does Asynchronous Programming work in Node.js?

Asynchronous programming is a cornerstone of Node.js and this question often tests your practical understanding of it.

Tips to answer this question:

  • Definition of Asynchronous Programming- Asynchronous Programming is a technique that allows a program to run multiple tasks simultaneously, without waiting for each task to finish before starting the next one.

  • Explain how it works-  In Node.js, asynchronous programming allows the server to handle multiple requests at once without waiting for each task to complete before moving on to the next. This is achieved through callbacks, promises, and async/await.

  • Explaining with an example, such as reading a file asynchronously and processing the data without blocking the server, can help clarify this concept.


Conclusion

Acing interviews is not just about knowing the answers but also about how you communicate them. It is like a gift wrapping on your skills, which won’t look so special if presented without one. 

At the same time do not divert from the quality of your presents- skills, since this is what forms the base of your interview.

Keeping these tips in mind will help you immensely in impressing your interviewers and becoming the top choice for any job selection. 

Good luck on acing your upcoming interviews!