The Exponent Android SDK by Exponent can access the API to implement contacts, camera, and social login. Exponent integration tests present how to configure the interface. Additional documentation available at https://facebook.github.io/react-native/docs/android-building-from-source.html
Forrst is a community for developers and designers to connect and collaborate. On Forrst users can share links, code, and in-progress projects, as well as discuss these things. This sort of community is always useful, as many eyes on projects can lead to spotting errors faster and making things more efficient for everyone involved. However, a simple website isn't all that's needed for true community-building these days. Developers and designers are the sort of people that use mobile devices extensively, and also the sort who love mashups and the like to save time and effort. For those people, Forrst has recently released the Forrst API, allowing access to Forrst through RESTful calls. And since that's the sort of feature developers want to see, they've been clamoring for Forrst's API, despite the site itself still in closed beta.