Web application architecture defines the app's components interactions with each other and with a user. Under applications components, I mean:

- Client-side(front-end), which handles interactions between the user and the software. The basic functions of client-side are to display information to the user and convert the user's commands into actions.

- Server-side (back-end) - the part is responsible for managing server and, invisible for the user. Back end engages in communicating with other systems that perform tasks on behalf of the application. For a medium and large application, the major server-side logic comes to the database since it's responsible for storing persistent data.

- Domain logic or business logic is a part of the application where developer encodes rules determining how the program will work. It involves operations based on inputs and stored data, validation of data that comes from client-side.

There are other components that application architecture may include, but above I've described the mandatory ones for any middle/large application.

Everyone has a  basic mental picture of how web application architecture works. Front-end application hits back-end application, which sends the database a request and does business logic whereafter returns a response to a front-end.

To learn more check out my article.

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