Continuing the discussion from GetPort: Application failed to start on container fossil-sage:
Right now, HyperDev apps have a single port connected to the public internet, and we inject that port number into your app using the PORT environmental variable. HTTP and HTTPS traffic to .hyperdev.space will come through that port. It’s currently 3000 (as that’s a common convention for Node apps), but we strongly recommend using the environmental variable to avoid 
maintenance headaches should we make changes down the line.
Need more ports? Cool! Help us learn about your use case over in Feature Ideas so we can consider how it fits with our vision 