A Single Page Application (SPA) is a web application that interacts with the user by dynamically rewriting the current page rather than loading entire new pages from the server. This approach provides a more fluid user experience, akin to a desktop application. Here are some key characteristics and benefits of SPAs:

1. Dynamic Content Loading: SPAs load content dynamically without refreshing the entire page. They use AJAX (Asynchronous JavaScript and XML) requests to communicate with the server, fetching data as needed and updating the web page accordingly.

2. Improved User Experience: Because SPAs do not require full page reloads, they offer a smoother and faster user experience. Navigation between sections of the application is quick, and the app feels more responsive.

3. Client-Side Routing: SPAs typically use client-side routing to manage different views or sections within the application. This is often handled by JavaScript frameworks or libraries such as React, Angular, or Vue.js.

4. Reduced Server Load: Since SPAs request data and not entire pages, the server load is reduced. This can lead to performance improvements and scalability benefits.

5. Caching: SPAs can cache data locally, making it possible to work offline or reduce the number of requests to the server.

6. SEO Considerations: Traditionally, SPAs have been challenging for search engine optimization (SEO) because they rely heavily on JavaScript to render content. However, modern techniques like server-side rendering (SSR) and pre-rendering have mitigated these issues.