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Glossary Web & HTTP

Cookie

A cookie is a small piece of data a website stores in your browser and sends back with later requests, used to remember logins and preferences.

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In more detail

Because HTTP is stateless, a session cookie is how a site recognises you after you log in. Security attributes matter: Secure (HTTPS only), HttpOnly (hidden from scripts) and SameSite (limits cross-site sending). Third-party cookies, set by other sites embedded in a page, are used for tracking and are being phased out by many browsers.

Try these tools

Cookie Inspector

Paste a raw Set-Cookie header string and instantly see its name, value, and every attribute (Expires, Domain, Path, Secure, HttpOnly.

Browser Storage Inspector

Inspect this page's live localStorage, sessionStorage, and accessible cookies in a readable table.

See also

  • Glossary HTTP
    HTTP (Hypertext Transfer Protocol) is the protocol browsers and servers use to request and send web pages, files and data.
  • Glossary CSRF
    CSRF (cross-site request forgery) is an attack that tricks a logged-in user's browser into sending an unwanted request to a site where they.
  • Cheat sheet HTTP Headers Cheat Sheet
    Request and response headers, Cache-Control directives, security headers, cookie attributes and CORS headers.
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