The CityGrid Ruby SDK by CityGrid provides installation, configuration, and sessions as part of the resources included on GitHub. Although still in development, author recommends to use the latest development. To start, obtain a publisher code at http://developer.citygridmedia.com/
PayOnDelivery, online payment platform that doesn't charge until delivery, has announced the PayOnDelivery API. Third party apps and websites may use the API to integrate payment processing. Developers have full access to the PayOnDelivery platform, including its keystone feature that refuses to release funds until the product lands in a consumer's hands.