Hey Railway team! 👋

I'm having persistent WebSocket connection issues with my Reflex (Python web framework) app deployed

on Railway. The frontend loads perfectly, but WebSocket connections fail immediately.

Error Pattern:

• ✅ Frontend loads correctly
• ❌ WebSocket connection to wss://my-app.up.railway.app/_event fails
• ❌ Browser shows "101 Switching Protocols" response followed immediately by connection close
• ❌ Error: "WebSocket is closed before the connection is established"

What I've Tried:

1. Single PORT approach: Backend listening on $PORT environment variable
2. Backend-only deployment: Serving static frontend from backend on same port
3. Header simplification: Removed potentially problematic proxy headers
4. Debug logging: Enabled --loglevel debug but no websocket-specific errors shown

Current Configuration:

nixpacks.toml

[start]

cmd = 'reflex run --backend-only --env prod --backend-host 0.0.0.0 --backend-port $PORT'

Key Details:

• Backend starts successfully on Railway's PORT
• /ping endpoint works fine (returns pong)
• WebSocket server should be accessible at /_event
• Same codebase works locally with websockets
• Using Reflex 0.8.11 (Python web framework with Socket.IO-based websockets)

Questions:

1. Are there any Railway-specific WebSocket limitations I should know about?
2. Do I need special configuration for WebSocket upgrades?
3. Any suggestions for debugging WebSocket connection issues on Railway?