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304 Not Modified

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 compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
304 Yes 12 Yes Yes Yes Yes
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
304 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

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/304