170716 2017-04-10 21:54:32 -0700 HTTP cache should cache regardless of status code when freshness information is available 2017-04-12 22:47:57 -0700 1 1 1 Unclassified WebKit Page Loading Safari Technology Preview All All NEW P2 Normal --- 1 mnot webkit-unassigned beidson koivisto mike oldest_to_newest 1296279 0 mnot 2017-04-10 21:54:32 -0700 In HTTP, the status code doesn't have much impact on caching. Specifically, if a response has an explicit freshness lifetime and there aren't any other conditions preventing caching (e.g., method, other cache directives in the request or response), the status code doesn't matter. Spec: http://httpwg.org/specs/rfc7234.html#caching.overview Allowing new status codes to be cached is important; it allows new extensions to be deployed without updating existing cache implementations. In testing, Safari TP appears to cache some status codes, but does not cache unknown status codes (e.g., 299, 499, 599), nor does it cache 5xx-series status codes (e.g., 500, 502, 503, 504). Chrome caches all of these status codes when they have explicit freshness information. Tests: http://w3c-test.org/fetch/http-cache/status.html