What is the difference between cache and cookie?

Cookie — these are small pieces of data sent by a web server to a browser, which the browser stores and sends back to the server on subsequent requests. They are used to store session information, authentication, user preferences, etc. Cookies have size limitations (usually up to 4 KB) and can have a lifespan.

Cache — this is a mechanism for storing copies of resources (such as HTML, CSS, JS, images) to speed up page loading. The browser or proxy server locally saves these resources so that they are not downloaded again from the server on subsequent requests. Cache is managed through HTTP headers (Cache-Control, ETag, etc.) and can have different update policies.

Main differences:

• Cookies are intended for storing user and session-related data and are sent to the server with each request.
• Cache stores copies of resources to optimize loading and is not sent directly to the server.
• Cookies are limited in size and used for data, cache for files and resources.

Example: a cookie can store an authentication token, while cache stores a saved copy of a website image.