Network requests and long-running tasks should not freeze the page. Asynchronous JavaScript lets the browser remain responsive while waiting for data, which is essential for modern web applications.

Promises represent values that will be available in the future, and $async/await$ makes promise-based code read more like synchronous flow. Under the hood, the browser still handles the operation asynchronously.

Front-end applications often communicate with APIs that return data in JSON. After receiving a response, you may parse it, render it into the DOM, and handle loading or error states for a smooth user experience.

Good interfaces communicate loading, success, empty, and error states clearly. This prevents uncertainty and gives users feedback when data is being fetched or processed.