What is the difference between session and application state in ASP.NET?

In ASP.NET, Session state and Application state are two different ways to store data that can be shared between pages in a web application.

Session state is used to store data that is specific to a particular user session. It allows you to store and retrieve values for a user as they navigate from page to page within your web application. Session state is stored on the server, and a unique session ID is sent to the client's browser to associate the user's requests with their specific session data on the server. The session data is available to all pages in the same web application, but is not shared between different applications on the same server.

Application state is used to store data that is shared among all users of an application. It is stored in memory on the server, and is available to all pages and users of the application. The data in the application state can be modified by any user of the application, so it is important to make sure that any shared data is accessed and updated in a thread-safe manner. Unlike session state, application state is shared between all users and sessions in the same web application.