HTTP 504 Gateway Timeout

Server error code, RFC 9110, section 15.6.5

What it means

A gateway or proxy did not get an answer from the server behind it in time.

A real response

This is the request and the answer our test server gave when we asked it to return 504.

GET /c/504 HTTP/1.1
Host: example.com

HTTP/1.1 504 Gateway Timeout
Date: Sat, 14 Nov 2026 10:00:00 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 11

<p>demo</p>

If you run the site

The application behind the proxy is too slow or stuck: a slow database query, an external service that does not answer, or too small a timeout in the proxy. Find the slow part in the application logs; increasing the proxy timeout hides the problem and keeps visitors waiting.

If you are a visitor

Reload after a few minutes. It is on the site's side.

A common mistake

Only raising the timeout instead of finding the slow request.

Registered in the IANA HTTP Status Code Registry as Gateway Timeout, defined in RFC 9110, section 15.6.5.

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.