What is the main function and purpose of cookies in web work?

Cookies are small pieces of data that a web server stores on a user's device through a browser. Their main function is to store session information and user preferences to provide a personalized experience during subsequent visits.

For example, cookies can remember that a user has logged in, so they don't have to log in again when navigating between pages.

In iOS, the HTTPCookieStorage class is used to work with cookies, allowing you to save, retrieve, and delete cookies for web requests.

Thus, cookies help maintain state between requests in the HTTP protocol, which is inherently stateless.