Mojo moves the URL definition of your app to the file urls.py, this file contains a list object called url_patterns that contains tuples mapping a URL to a RequestHandler in your views.py.
All entries work the same way as they do with standard Tornado mappings, when your server starts up, Mojo will automatically concatenate all the URL’s for you into a single pattern set to ensure that all your apps are available in the project without mixing functionality across apps:
from views import myRequestHandler
urlpatterns = [
('/hello', myRequestHandler),
]
All URL patterns can be regex groups - see the Tornado documentation for more details on how to use the URL routing in a Tornado app.