No, not localhost. But you can make the built-in debugging server bind to all IP addresses, including the one used on your WLAN.

In backend/local_server.py, change the line that says:

    app.run()

to instead read:

    app.run(host='0.0.0.0')

You should then be able to access the server at the WLAN IP address of your machine, provided port 5000 is opened by your firewall.

Even better, however, would be to use uwsgi in standalone mode. I've updated the README with instructions on this.