We're experimenting with Vagrant virtual machines for development.

To use your host machine browser against a virtual machine web server, Vagrant must forward some host machine port to the server's port.

So on your host machine, you may use http://localhost:8001 for app1 and http://localhost:8002 for app2.

This avoids port conflicts, but it's a bit rough.

If you have Pow installed on your OS X host machine, though, you can use its port proxying feature. Just do this:

echo 8001 > ~/.pow/app1
echo 8002 > ~/.pow/app2

You can now use http://app1.dev instead of http://localhost:8001, and http://app2.dev instead of http://localhost:8002.