Node.js technical interview questions and answers are essential for candidates preparing for backend development, full-stack development, and server-side programming roles. Companies like TCS, Infosys, Wipro, Accenture, and Capgemini frequently test your understanding of asynchronous programming, event loops, Express.js, APIs, middleware, error handling, database integration, and performance optimization. Technical interviewers evaluate your ability to build scalable, efficient, and secure backend applications using Node.js and its ecosystem.
These questions help freshers, job seekers, and working professionals strengthen their concepts and improve their coding abilities during real interviews. Node.js interviews often include scenario-based questions, live coding challenges, and practical backend tasks to test your problem-solving skills. This guide provides the most important technical interview Q&A to help you revise key topics, practice mock questions, and become interview-ready for top IT companies and campus placements.
Showing 5 of 25 questions
21. What is the difference between process.env and dotenv in Node.js
process.env is a global object in Node.js that holds environment variables, while dotenv is a module that loads environment variables from a .env file into process.env, making it easier to manage environment-specific variables.
22. How does Node.js handle file system operations
Node.js provides the fs module to handle file system operations. It supports both synchronous and asynchronous methods for reading, writing, and manipulating files and directories.
23. What is the purpose of the package-lock.json file
The package-lock.json file ensures that the exact versions of dependencies are installed in a Node.js project. It locks the versions of installed packages and their dependencies, preventing any unwanted changes in subsequent installations.
24. How do you secure a Node.js application
Securing a Node.js application involves using HTTPS, validating and sanitizing user inputs, using environment variables for sensitive data, regularly updating dependencies, and implementing security headers.
25. Explain the purpose of the crypto module in Node.js
The crypto module in Node.js provides cryptographic functionality, including encryption, decryption, hashing, and digital signatures. It is used to secure data in various parts of an application.