What is an API?
What are HTTP methods?
What is JSON?
What is status code 200?
. Why should API Keys not be stored in Frontend?
Because anyone can inspect frontend code and steal the API key.
Difference between callbacks and promises?
What is Request Lifecycle?
Request arrives.
Middleware executes.
Route handler executes.
Business logic runs.
Response sent back.
. Why use Environment Variables?
To keep sensitive information secure and separate from source code.
What is CORS?
What is rate limiting?
What is MongoDB?
What is the V8 Engine?
Answer: Google's JavaScript engine used by Chrome and Node.js.
What is package.json?
Answer: A file containing project metadata and dependencies.
Why is Node.js fast?
Answer: Because it uses the V8 engine and non-blocking I/O.
What is a route parameter?
Answer: Dynamic value in URL (e.g., /user/:id).
What is centralized error handling?
Answer: Handling all errors through one middleware.
What happens if next() is not called?
Answer: Request may hang and never reach the response.
What is status code 401?
Answer: Unauthorized.
What is status code 400?
Answer: Bad request.
What is bcrypt?
Answer: Library for password hashing.
What is an access token?
Answer: Short-lived token for API access.
What is a session?
Answer: Server-side user state storage.
What is JWT?
Answer: JSON Web Token for authentication.
Difference Betweem authentication and authorization?
Answer:
Authentication - Verifying user identity.
Authorization - Checking user permissions.