Curriculum
- 11 Sections
- 35 Lessons
- 10 Weeks
- Introduction to Backend Development5
- JavaScript for Backend (Core Concepts)4
- Node.js Fundamentals4
- Building Server with Express.js4
- REST API Development4
- Database with MongoDB4
- Authentication & Security2
- Advanced Backend Concepts3
- Deployment & DevOps Basics1
- Real Project1
- Career & Interview Preparation3
Node.js Interview Questions and Answers
Node.js Interview Questions and Answers – Complete Guide for 2026
Node.js interview questions are important for backend developer roles. In this guide, you will find top Node.js interview questions and answers covering basics, intermediate concepts, and advanced topics. This will help you prepare for real interviews and improve your backend knowledge.
Basic Node.js Interview Questions
What is Node.js
Node.js is a runtime environment that allows you to run JavaScript on the server side. It is built on Chrome’s V8 engine and is used to build scalable backend applications.
What are the key features of Node.js
Node.js is asynchronous, non-blocking, fast, and event-driven. It is designed for building scalable network applications.
What is npm in Node.js
npm (Node Package Manager) is used to install, manage, and update packages in Node.js projects.
What is package.json
package.json is a file that contains project metadata, dependencies, and scripts.
Intermediate Node.js Interview Questions
What is the Event Loop in Node.js
The event loop handles asynchronous operations. It allows Node.js to execute non-blocking tasks using callbacks and queues.
What is Callback in Node.js
A callback is a function passed as an argument to another function. It runs after the task is completed.
What are Promises
Promises are used to handle asynchronous operations. They have three states: pending, fulfilled, and rejected.
What is async/await
async/await is a modern way to write asynchronous code. It makes code cleaner and easier to understand.
Backend and API Questions
What is Express.js
Express.js is a web framework for Node.js used to build APIs and web applications.
What is Middleware in Express.js
Middleware is a function that runs between request and response. It is used for logging, authentication, and validation.
What is REST API
A REST API is a way for client and server to communicate using HTTP methods like GET, POST, PUT, and DELETE.
Advanced Node.js Interview Questions
What is JWT Authentication
JWT (JSON Web Token) is used for secure authentication. It allows stateless authentication using tokens.
What is MVC Architecture
MVC is a design pattern that separates application into Model, View, and Controller.
What is Clustering in Node.js
Clustering allows Node.js to use multiple CPU cores by running multiple instances of the application.
What is Stream in Node.js
Streams are used to handle large data efficiently by processing it in chunks.
Coding-Based Questions
Create a simple HTTP server
const server = http.createServer((req, res) => {
res.end(“Hello Node.js”);
});
server.listen(3000);
Read a file in Node.js
fs.readFile(‘test.txt’, ‘utf8’, (err, data) => {
console.log(data);
});
Scenario-Based Questions
How do you handle errors in Node.js
Use try-catch, centralized error middleware, and proper logging.
How do you secure APIs
Use JWT authentication, input validation, HTTPS, and rate limiting.
How do you improve performance
Use caching, clustering, database optimization, and async programming.
Important Topics to Revise
- Event Loop
- Middleware
- REST APIs
- Authentication (JWT)
- MVC Architecture
- Error Handling
Tips to Crack Node.js Interview
- Focus on core concepts
- Practice coding regularly
- Build real-world projects
- Understand API design
- Prepare scenario-based answers
Internal Link
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FAQs
Is Node.js good for interviews
Yes, Node.js is widely used in backend development roles.
What topics are most important
Event loop, APIs, authentication, and async programming.
Do companies ask coding questions
Yes, basic coding and logic questions are common.
How to prepare quickly
Revise concepts and practice real examples.