Server-side JavaScript, REST APIs, authentication, and testing.
What Node.js is, the event loop, npm, and your first server.
Build a web server with Express: routes, middleware, request/response handling.
Designing clean REST APIs: HTTP methods, status codes, versioning, and best practices.
JWT, sessions, bcrypt, role-based access control, and secure password storage.
Test Express APIs with Jest and Supertest. Centralized error handling and validation.