Cacheable

A cacheable response is an HTTP response that can be cached, that is stored to be retrieved and used later, saving a new request to the server. Not all HTTP responses can be cached; these are the constraints for an HTTP response to be cacheable:

The method used in the request is cacheable, that is either a GET or a HEAD method. A response to a POST or PATCH request can also be cached if freshness is indicated and the Content-Location header is set, but this is rarely implemented. For example, Firefox does not support it (Firefox bug 109553). Other methods, like PUT or DELETE are not cacheable and their result cannot be cached. The status code of the response is known by the application caching, and is cacheable. The following status codes are cacheable: 200, 203, 204, 206, 300, 301, 404, 405, 410, 414, and 501. There are no specific headers in the response, like Cache-Control, with values that would prohibit caching.