What is the primary purpose of cookies in web development?

The primary purpose of cookies in web development is to store user preferences and data. Cookies are small text files that are placed on the user's device when they visit a website. This functionality allows the website to remember information about the user between visits, such as login credentials, language settings, and items in a shopping cart.

By saving this information, cookies significantly enhance the user experience by allowing a website to provide a more personalized interaction. For example, if a user selects a preferred language on a website, that preference can be saved in a cookie, enabling the site to automatically display content in that language on future visits.

Additionally, cookies can also store analytics data, but their primary role is not tracking website traffic more broadly, which involves server-side analytics and is handled through other means, such as log files or external tracking services. While cookies can contribute to improved server performance by reducing the amount of data that needs to be sent and re-processed, that is more of a secondary benefit rather than their main purpose.