Answer by Elijah Saounkine for How can I access my localhost from my Android device?

USB doesn't provide network to mobile device.

If both your desktop and phone are connected to the same WiFi (or any other local network), then use your desktop IP address assigned by the router (not localhost and not 127.0.0.1).

To find out the IP address of your desktop:

• type into the command line ipconfig (Windows) or ifconfig (Unix)
  • on Linux the one-liner ifconfig | grep "inet " | grep -v 127.0.0.1 will yield only the important stuff
  • there's a bunch of suggestions on how to have a similar output on Windows
• there's going to be a bunch of IP's
• try all of them (except the forementioned localhost and 127.0.0.1)

If your phone is connected to the mobile network, then things are going to be harder.

Either go hardcore:

• first find out your router external IP address (https://www.google.de/search?q=myip)
• then, on the router, forward some port to <your desktop IP>:<server port number>
• finally use the external IP address and forwarded port

Otherwise use something like xip.io or ngrok.