Client-side programming runs in the user's browser and is responsible for the user interface, interactivity, and immediate feedback. Examples include HTML, CSS, and JavaScript. It handles tasks like form validation, animations, and dynamic content rendering.

Server-side programming runs on the server and handles data processing, database interactions, authentication, and business logic. Examples include PHP, Python, Node.js, and Java. It generates responses to client requests, like rendering HTML or sending JSON data.

The key difference: client-side focuses on user experience, while server-side focuses on backend logic and data management. Both often work together to create dynamic, interactive web applications.