2 months ago
Hello,
I often experience an issue where the application works normally, and then suddenly it starts returning a lot of 499 and 502 errors.
What is strange is that my server does not generate these errors at all. I checked the logs, and these status codes are clearly not coming from my application. This strongly suggests that the problem is happening on the Railway side, most likely somewhere in the proxy or infrastructure layer.
The only thing that helps is a restart/reset, and recently this has been happening quite often.
Could you please explain what might be causing this and check whether there is an issue on your side?
Thank you.
1 Replies
2 months ago
This does not necessarily look like a Railway-wide outage. The 499 and 502 codes usually point to two different issues:
- 502 means Railway’s edge proxy could not successfully talk to your app instance.
- 499 usually means the client/proxy gave up waiting because the upstream app stopped responding in time.
A useful way to narrow this down is:
1. Check Deployment -> HTTP Logs and filter @httpStatus:502.
2. Inspect the upstreamErrors field for failing requests.
3. Verify the app is listening on 0.0.0.0:$PORT and that the domain target port matches the actual app port.
4. Check whether the process is hanging on DB/Redis/external API calls, because that can produce 499s without obvious application logs.
5. If upstreamErrors suggests broken reused connections / unexpected close, try increasing the server keepalive timeout and/or running more than one replica.
Why restart appears to help:
A restart can temporarily clear a stuck process, stale upstream connection, or blocked dependency call, but that alone does not prove the root cause is Railway infrastructure.
If you share one or two failing request IDs, timestamps, region, and the exact upstreamErrors value from HTTP logs, it should be possible to tell whether this is:
- a bind/port issue,
- an upstream keepalive / connection reuse problem,
- or an application/dependency hang.