The transient keyword is a keyword that can be used to declare instance variables that are not part of the view state of a Visualforce page. The view state is the state of the page that is persisted on the server and transferred to the client. The view state can affect the performance and user experience of the page, as it can increase the page load time, the response time, and the bandwidth consumption. By using the transient keyword, the developer can mark the variables that are not needed for rendering the page or maintaining the state, such as temporary variables, constants, or cached data. This way, the developer can reduce the size of the view state and improve the performance of the page. Reference: [transient Keyword], [View State]