How do web applications work?

Web applications operate on a client-server architecture:

1. Client (usually a browser) sends an HTTP request to the server, for example, when entering a URL or clicking a button.
2. Server receives the request, processes it — it may access a database, perform business logic.
3. The server forms an HTTP response — this can be an HTML page, JSON data, or other resources.
4. The client receives the response and displays the information to the user.

Frontend is the part that runs on the client side (HTML, CSS, JavaScript), and backend runs on the server (for example, Python, Java, Go).

Thus, a web application is a set of components that interact over the network via the HTTP protocol, providing dynamic interaction with the user.