The Realm iOS & iOS X SDK in Objective-C provides developers access to the functionality of Realm for integration with other applications and devices. Realm is a mobile database and can be used as a replacement for SQLite and Core Data.
Read-it-later service Instapaper has released what it's calling a "full API." With it, developers using the Instapaper API can create applications that both write to and read from the service. The full API is free to developers, but only paying users can read from their Instapaper account using third-party tools.
Multi-factor authentication platform provider LaunchKey has announced new API integrations for web and mobile applications. The LaunchKey platform improves privacy and security through decentralization of credentials from personal identification information. In addition to native apps, LaunchKey offers a central API, multiple SDKs and plugins that allow for cross-platform integration with mobile devices.