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 ModifiedSpecifications
| Specification | Title |
|---|---|
| RFC 7232, section 4.1: 304 Not Modified | Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests |
Browser compatibility
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The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Compatibility Notes
- Browser behavior differs if this response erroneously includes a body on persistent connections See 204 No Content for more detail.