If you are building a web application using Google App Engine you might be interested in testing it with your smartphone ( note: for this post, we suppose your appengine server and your smartphone are conected to the same network). This is how I manage to do it.

Get your IP:

First thing to do it to get the IP where the server is running (in this case 192.168.1.X):
On a mac use a ifconfig.

> ifconfig
inet 192.168.1.X netmask 0xffffff00 broadcast
On a windows machine you would do a ipconfig.

Run your app with the host parameter:

Next you run the app with the -host parameter set to

> goapp serve -host=
INFO 2014-04-26 10:25:33,296 devappserver2.py:764] Skipping SDK update check.
WARNING 2014-04-26 10:25:33,299 api_server.py:374] Could not initialize images API; you are likely missing the Python "PIL" module.
INFO 2014-04-26 10:25:33,302 api_server.py:171] Starting API server at: http://localhost:53542
INFO 2014-04-26 10:25:33,305 dispatcher.py:182] Starting module "default" running at:
INFO 2014-04-26 10:25:33,307 admin_server.py:117] Starting admin server at: http://localhost:8000
Access your web app from your smartphone:

Finally access your web app from your smartphone with your IP like so: http://192.168.1.X:8080/

Some links that helped me find this: