In computing, a cookie (also tracking cookie, browser cookie, as well as HTTP cookie) is a tiny portion of text stored on a user's PC by a web browser. A cookie consists of one or else additional name-value pairs enclosing bits of details for example user preferences, shopping cart contents, the identifier for a server-based session, or else additional data used by some other websites.

It is send as an HTTP header by a web server to a web browser as well as after that sent reverse to the unaffected by the browser every time it accesses that server. A cookie can be used for validating, session tracking (state maintenance), as well as identifying precise information in relation to users, such as site preferences or else the contents of their electronic shopping carts. The word "cookie" is resultant from "magic cookie", a renowned conception in UNIX computing which encouraged both the thought as well as the given name of browser cookies. A few alternatives to cookies exist; each one has its own uses, benefits, as well as disadvantages.

Being simple pieces of text, cookies are not executable. They are neither spyware nor viruses, even though cookies from definite sites are being checked by lots of anti-spyware products as they can permit users to be followed when they visit different websites.

Most modern browsers enable customers to choose whether to allow cookies, plus the time frame to maintain them, but eliminating cookies makes several websites not viable. For instance, shopping carts or else login systems executed by means of cookies do not work if cookies are being deactivated.