What is a cookie in web technology?

A cookie in web technology is a small piece of data that is stored on a user's device by a web browser while browsing a website. Cookies are used to remember information about the user, such as login details, user preferences, shopping cart contents, and other relevant data that helps to enhance the user experience when visiting a site again. By storing this information, cookies allow websites to provide a more personalized and efficient interaction for users, essentially remembering their past activities and preferences.

For example, when you log in to a website, a cookie may be created to keep you logged in during your session or for your next visit. This functionality illustrates the primary role of cookies in facilitating stateful sessions and user-specific interactions in an otherwise stateless environment, such as the HTTP protocol.