The Dailymile Ruby SDK by Dailymile supports most points in the API, allowing developers to integrate fitness tracking features into social applications. Resources available to authenticate with OAuth and interact with REST protocols.
A brand new iOS messaging/social app called Peach has rocketed in popularity since launching last Friday. A developer has reverse engineered the Peach API and created clients for Swift and Mac. The clients have been posted on GitHub for developers interested in using the undocumented Peach API.