What is a cookie on a website?

A website cookie is a tiny text file that a web server sends to your web browser when you visit a site. Your browser stores this file on your computer or mobile device. The next time you load a page on that website, your browser sends the cookie back to the server. This simple transfer of data allows websites to remember who you are and customize your browsing experience.

Without cookies, the internet would have no memory. Because the basic protocol used to load web pages is stateless, a website cannot tell the difference between two separate clicks from the same user. Cookies solve this problem by assigning a unique identification code to your session. This identifier is what keeps you logged into your account as you click from page to page and prevents your shopping cart from emptying when you hit refresh.

There are different types of cookies, and they serve different purposes. First-party cookies are created directly by the website you are visiting, and they are usually harmless and helpful. Third-party cookies, however, are placed by external advertisers and tracking networks. These cookies follow your browsing habits across multiple websites, building a profile of your interests to show you targeted advertisements.

Because third-party cookies raise privacy concerns, modern browsers have started blocking them by default. You can manage your cookies in your browser’s security settings. Clearing your cookies regularly is a good way to reset your tracking profile, though you will have to log back into your accounts afterwards. Protecting your online privacy is a continuous task, and understanding how cookies work is a great first step.