index.md

---

title: 304 Not Modified
slug: Web/HTTP/Status/304
browser-compat: http.status.304

---

{{HTTPSidebar}}

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 a {{glossary("Safe/HTTP", "safe")}} method, such as {{HTTPMethod("GET")}} or {{HTTPMethod("HEAD")}}, or when the request is conditional and uses an {{HTTPHeader("If-None-Match")}} or an {{HTTPHeader("If-Modified-Since")}} header.

The equivalent {{HTTPStatus("200")}} OK response would have included the headers {{HTTPHeader("Cache-Control")}}, {{HTTPHeader("Content-Location")}}, {{HTTPHeader("Date")}}, {{HTTPHeader("ETag")}}, {{HTTPHeader("Expires")}}, and {{HTTPHeader("Vary")}}.

Note: 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

{{Specifications}}

Browser compatibility

{{Compat}}

Compatibility notes

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

See also

• {{HTTPHeader("If-Modified-Since")}}

• {{HTTPHeader("If-None-Match")}}