How is 'back-end' development defined?

Back-end development is defined primarily by its focus on server-side programming and application logic. This area of development deals with the components of a web application that users do not see directly. It encompasses the server, database, and application programming interfaces (APIs) that manage data exchange and business logic.

The server-side programming involves writing code that runs on the server, handling requests from clients, processing data, and sending back the appropriate responses. This often requires knowledge of server-side languages such as Python, Ruby, Java, or PHP, and frameworks that facilitate web development.

By concentrating on application logic, back-end developers ensure that the application's functionality is correctly implemented, and they create the rules and processes that govern how data is processed and stored. Hence, the accurate designation of back-end development is tied to these server-side elements, making it crucial for the overall performance and reliability of web applications.