Top 100 Node JS interview questions

Here’s a list of 100 Node.js interview questions that cover a range of topics, from basic to advanced concepts. These questions can help you prepare for interviews or assess your knowledge of Node.js. Here we are providing node js interview questions for experienced professionals as well as beginners

Basic Node js interview questions

1. What is Node.js?
2. What are the key features of Node.js?
3. Explain the event-driven architecture of Node.js.
4. What is the role of the V8 engine in Node.js?
5. How does Node.js handle asynchronous operations?
6. What is the difference between synchronous and asynchronous programming?
7. What is a callback function in Node.js?
8. What are Promises in Node.js?
9. Explain async/await in Node.js.
10. What is the purpose of the require function in Node.js?

Intermediate Questions

11. What is the Node Package Manager (NPM)?
12. How do you create a simple HTTP server in Node.js?
13. What is middleware in Express.js?
14. Explain the concept of streams in Node.js.
15. What are the different types of streams in Node.js?
16. How do you handle errors in Node.js?
17. What is the purpose of the process object in Node.js?
18. How can you read and write files in Node.js?
19. What is the difference between fs.readFile and fs.createReadStream?
20. Explain the concept of the event loop in Node.js.

Advanced Questions node js interview questions for senior developer

21. What is clustering in Node.js?
22. How can you improve the performance of a Node.js application?
23. What are worker threads in Node.js?
24. Explain the concept of microservices in the context of Node.js.
25. What is the purpose of the package.json file?
26. How do you manage environment variables in Node.js?
27. What is CORS and how do you handle it in Node.js?
28. Explain the concept of session management in Node.js.
29. What is the difference between process.nextTick() and setImmediate()?
30. How do you implement logging in a Node.js application?

Database Questions

31. How do you connect to a MongoDB database using Node.js?
32. What is Mongoose and how is it used in Node.js?
33. Explain the differences between SQL and NoSQL databases.
34. How do you perform CRUD operations in Node.js?
35. What is an ORM and how does it relate to Node.js?

Security Questions

36. How do you secure a Node.js application?
37. What is JWT and how is it used in Node.js?
38. Explain the concept of rate limiting in Node.js.
39. How do you prevent SQL injection in Node.js applications?
40. What are some common security vulnerabilities in Node.js?

Testing Questions

41. How do you test a Node.js application?
42. What is Mocha and how is it used?
43. Explain the purpose of Chai in testing Node.js applications.
44. How do you mock dependencies in Node.js tests?
45. What is the difference between unit testing and integration testing?

Performance Questions

46. How do you profile a Node.js application?
47. What tools can you use to monitor Node.js applications?
48. Explain the concept of load balancing in Node.js.
49. How do you handle memory leaks in Node.js?
50. What is the purpose of the pm2 process manager?

Frameworks and Libraries

51. What is Express.js?
52. How do you create RESTful APIs using Express.js?
53. What is Socket.io and how is it used in Node.js?
54. Explain the purpose of the body-parser middleware.
55. What is Koa.js and how does it differ from Express.js?

Deployment Questions

56. How do you deploy a Node.js application?
57. What is Docker and how can it be used with Node.js?
58. Explain the concept of serverless architecture in Node.js.
59. How do you use environment variables in production?
60. What are some common cloud platforms for deploying Node.js applications?

Miscellaneous Questions

61. What is the difference between let, const, and var in JavaScript?
62. Explain the concept of closures in JavaScript.
63. What are arrow functions and how do they differ from regular functions?
64. How do you handle promises in Node.js?
65. What is the purpose of the this keyword in JavaScript?

Real-World Scenarios

66. How would you handle file uploads in a Node.js application?
67. Describe a situation where you had to optimize a Node.js application.
68. How do you implement pagination in a Node.js API?
69. What strategies would you use to handle large amounts of data in Node.js?
70. How do you implement authentication in a Node.js application?

Best Practices

71. What are some best practices for writing Node.js code?
72. How do you structure a Node.js application?
73. What is the importance of using a linter in Node.js projects?
74. How do you manage dependencies in a Node.js application?
75. Explain the concept of code modularization in Node.js.

Error Handling

76. How do you handle uncaught exceptions in Node.js?
77. What is the purpose of the try...catch statement in Node.js?
78. How can you create custom error classes in Node.js?
79. Explain the concept of error-first callbacks.
80. How do you log errors in a Node.js application?

Asynchronous Programming

81. What are the benefits of using async/await over callbacks?
82. How do you handle multiple asynchronous operations in Node.js?
83. What is the Promise.all() method and how is it used?
84. Explain the concept of race conditions in asynchronous programming.
85. How do you cancel a promise in Node.js?

API Development

86. How do you implement versioning in a Node.js API?
87. What is GraphQL and how does it differ from REST?
88. How do you handle API rate limiting in Node.js?
89. Explain the concept of API documentation and its importance.
90. How do you test APIs in a Node.js application?

Networking

91. What is the difference between HTTP and HTTPS?
92. How do you create a WebSocket server in Node.js?
93. Explain the concept of DNS and how it relates to Node.js applications.
94. How do you handle cross-origin requests in Node.js?
95. What are the differences between TCP and UDP?

Advanced Topics

96. What is the purpose of the EventEmitter class in Node.js?
97. How do you implement caching in a Node.js application?
98. Explain the concept of message queues and how they can be used with Node.js.
99. What are the benefits of using TypeScript with Node.js?
100. How do you implement GraphQL in a Node.js application?

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