What are HTTP Cookies?

HTTP Cookies — also known as web cookies, browser cookies, or simply just cookies — are small pieces of data sent from a web server to a user’s browser.

Although it depends on how a website or application uses cookies, a user’s web browser will typically store a cookie sent from a server as a way to retain persistent information about the user even after they leave the given website. Examples of the type of information a cookie might hold include a user’s login information, the items they’ve placed in their shopping cart, or their user settings and preferences.

Cookies consist of a name and a value. For example, a cookie used for session management might have a name like usr_session, and the server might automatically generate a unique session ID as that cookie’s value. In addition, cookies can optionally have one or more additional name-value pairs that define certain attributes, like the cookie’s expiration or various security settings.