Rendering maps from vector data is the next wave in custom cartography, and nowhere is this more important than on mobile devices. Modern mobile devices have high-powered GPUs for hardware-accelerated rendering and a multitude of sensors for environmental input, but also need to be keenly aware of network bandwidth constraints and have the ability to go offline. Mapbox is working on a new suite of mobile tools that render constantly up-to-date vector OpenStreetMap data into maps on the device. These maps can be customized completely client-side and even tap into ambient sensors such as GPS, compass, and pedometer. This session will show what's possible with this new open source toolkit, including client-side map style customization and influencing the user experience with sensor inputs, and will talk about high-level design goals of the tools and where they are headed next.