Backend Development

Question 1

What is Node.js, and how does it work?

Answer 1

Node.js is a runtime environment that allows JavaScript to run on the server. It uses an event-driven, non-blocking I/O model.

Question 2

What is Express.js?

Answer 2

Express.js is a web application framework for Node.js that simplifies building APIs and web applications.

Question 3

What is REST, and how does it work?

Answer 3

REST is an architectural style for designing networked applications. It uses HTTP methods (GET, POST, PUT, DELETE) to perform CRUD operations.

Question 4

What is the difference between SQL and NoSQL databases?

Answer 4

SQL databases are relational (e.g., MySQL, PostgreSQL). NoSQL databases are non-relational (e.g., MongoDB, Cassandra).

Question 5

What is JWT (JSON Web Token)?

Answer 5

JWT is a compact, URL-safe token format used for securely transmitting information between parties as a JSON object.

Question 6

What is middleware in Express.js?

Answer 6

Middleware are functions that have access to the request and response objects. They can modify requests, perform authentication, or log data.

Question 7

What is the difference between authentication and authorization?

Answer 7

Authentication verifies a user’s identity (e.g., login). Authorization determines what a user is allowed to do (e.g., access control).

Question 8

What is a session, and how is it different from a cookie?

Answer 8

A session is server-side storage of user data. A cookie is client-side storage of small data (e.g., session ID).