The Google Data Transfer Objective-C SDK by Google provides the tools for an iOS application to make requests to the Data Transfer API. The Google Data Transfer API is a service for developers that assists with the management of transferring data from one user to another within a domain.
Stannp.com is a free app that allows users to quickly and easily create their own custom-made postcards. The company provides the Stannp API that allows developers to integrate this tool into other applications. By snapping a picture or using an existing image, the user has the option to customize the image with fun effects and add the finished product to their Facebook wall, email it to a friend or have it turned into a real postcard to be posted the same day.