HTTP 304 Not Modified

Redirection code, RFC 9110, section 15.4.5

What it means

What you already have saved is still the current version, so no body is sent. The server answers this when your request said "send it only if it changed" and it did not.

A real response

This is the request and the answer our test server gave when we asked it to return 304.

GET /c/304 HTTP/1.1
Host: example.com

HTTP/1.1 304 Not Modified
Date: Sat, 14 Nov 2026 10:00:00 GMT
Content-Type: text/html; charset=utf-8
ETag: "v7"

If you run the site

Send an ETag or Last-Modified header with files. The browser then asks next time with If-None-Match or If-Modified-Since, and your server can answer 304, which saves bandwidth. The response must repeat the cache headers that a 200 would have had, such as ETag and Cache-Control.

If you are a visitor

Nothing to fix. It means the page came from your own saved copy, after a check with the server.

A common mistake

Sending a body with a 304, or sending a 304 without the ETag of the version you mean.

Registered in the IANA HTTP Status Code Registry as Not Modified, defined in RFC 9110, section 15.4.5.

This is an independent guide. It is not connected with the IETF, IANA, any browser maker or any company named here. Meanings were checked against the RFC texts on 14 November 2026. Responses shown were recorded on 14 November 2026 from a small test server on the author's own computer.