5xx Server Errors
HTTP 504 Gateway Timeout
The server acting as a gateway did not receive a timely response from the upstream server.
When is 504 used?
- Upstream server slow response
- Database timeout cascading to gateway
- Network latency between services
How to handle a 504 response
The problem is on the server side. Check server and proxy logs, retry idempotent requests with exponential backoff, and alert on sustained 5xx rates.
Check the status code a URL returns from the command line:
curl -s -o /dev/null -w "%{http_code}\n" https://example.comHow to return 504 from your server
Node.js (Express)
res.status(504).json({ message: 'Gateway Timeout' });Python (Flask)
return {"message": "Gateway Timeout"}, 504Go (net/http)
w.WriteHeader(504)Frequently Asked Questions
What does HTTP 504 mean?
504 Gateway Timeout: The server acting as a gateway did not receive a timely response from the upstream server.
Is 504 an error?
Yes. 504 is in the 5xx Server Errors class. Server errors: the server failed to fulfil an apparently valid request.