Summary  
This chapter explains how code can be separated into frontend (client-side UI interaction) and backend (server-side logic and data processing) components.

General domain of usage  
Web development

Every website or app is built from two main parts: frontend and backend.

The frontend is everything you can see and interact with. It includes the layout, text, buttons, forms, and all visual elements. This part runs in your browser.

The backend is everything that happens behind the scenes. It handles logic, processes data, and makes decisions. This part runs on a server.

To understand the difference, think about a simple login.

On the frontend, you see input fields for email and password. You type your data and click the login button.

On the backend, your data is received and checked. The system verifies if the user exists and if the password is correct. Then it sends back a result, either success or an error message.

The frontend shows the result, but the backend makes the decision.

The frontend is what the user sees and interacts with.

The backend is what makes the application actually work.

Note

Understand how the web works and what happens behind the scenes when you open a website. Learn the difference between frontend and backend and what role backend developers play. Build a clear foundation before starting real backend development with Node.js.

Frontend vs Backend