The Google Shopping Content Java SDK by Google aims to simplify API calls. An example shows hot to interact with Google Calendar, which can be useful to work with the Google Shopping Content API. Authentication Auth 2.0 intends to reduce the amount of code needed. See documentation available at https://github.com/google/google-api-java-client#Documentation
Strutta provides a platform to "engage your audience and convert fans to customers." It does this by launching and managing contests, sweepstakes, coupons, promotions, and by providing the Strutta API. For example, Crate & Barrel ran a wedding contest to drive couples to set up their wedding registries at the company, and featured friends and families of the contestants voting on the results to generate increased customer involvement.
Zinc bridges the gap between bloggers and content creators and the retailers that sell the products reviewed and covered. The Zinc API allows anyone with an online presence to add a few lines of code to a site or app and seamlessly add ordering functionality. Zinc integrates with various online retailers; so, readers/consumers no longer need to leave a site to order a product from a major online retailer.