I’m experiencing an issue with internal requests to my Railway service:

My service is a Node.js Express app listening on port 8080 (bound to ::).
It logs successful handling of requests (200 OK) and valid JSON response bodies in the logs.
When I call this endpoint from another container via .railway.internal, I get a 200 status but an empty response body.
Public requests via .up.railway.app work fine and return full JSON.
This happens even for tiny test responses (like { test: "hi" }), so it’s not a payload size or application-level issue.

Here’s what I’ve tried:

• Validated Express app is correctly listening on port 8080 and logging the outgoing response.

• Tested a /test endpoint to isolate from other application logic—still seeing an empty body internally.

• Verified it’s not related to response size—same problem for small and large JSON.

• Public .up.railway.app endpoint works flawlessly.

This suggests an issue in Railway’s internal IPv6 proxying or port exposure for internal .railway.internal traffic.