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The HTTP 304 Not Modified client redirection response code indicates that there is no need to retransmit the requested resources. It is an implicit redirection to a cached resource. This happens when the request method is safe, like a GET or a HEAD request, or when the request is conditional and uses a If-None-Match or a If-Modified-Since header.

The equivalent 200 OK response would have included the headers Cache-Control, Content-Location, Date, ETag, Expires, and Vary.

Many developer tools' network panels of browsers create extraneous requests leading to 304 responses, so that access to the local cache is visible to developers.

Status

304 Not Modified

Specifications

Specification Title
RFC 7232, section 4.1: 304 Not Modified Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic Support(Yes)(Yes)(Yes)(Yes)(Yes)(Yes)
FeatureAndroidChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic Support(Yes)(Yes)(Yes)(Yes)(Yes)(Yes)(Yes)

Compatibility Notes

  • Browser behavior differs if this response erroneously includes a body on persistent connections See 204 No Content for more detail.

See also

Document Tags and Contributors

 Contributors to this page: mtShaikh, jugglinmike, fscholz, teoli
 Last updated by: mtShaikh,