The route module makes it easy to add routing functionality to your web map.
The route module currently supports two different "modes": simple and multi-destination. Simple mode renders a user interface that allows the user to specify "from" and "to" destinations for their route. Multi-destination mode renders a user interface that allows the user to build an itinerary of up to fifteen destinations for their route. You can switch a map between the two modes by changing the "mode" property on the route module config object.
Better documentation and a more robust feature set is coming soon.