Use CMX REST APIs to develop a web based app or CMX Mobile SDK to develop a mobile application.
If you are doing a web based app use the native CMX REST APIs . Some code samples are available here : Deep Dive: Mobility Services APIs (with Sample Code!)
If you are planning to do a mobile application with a focus on wayfinding, use the CMX Mobile SDKs. Development tools and SDK are currently under development for CMX 10, please stay tuned for future announcements.