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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
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.
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
304 | Chrome Full support Yes | Edge Full support Yes | Firefox Full support Yes | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
Compatibility Notes
- Browser behavior differs if this response erroneously includes a body on persistent connections See 204 No Content for more detail.