The PayPal Express Checkout Ruby SDK by PayPal is a gem that allows developers to integrate the PayPal Express Checkout API into their Ruby applications. Rails 4+ is not supported due to backward compatibility concerns.
Bitpay's API allows for businesses and employees to accept BitCoin for their services and goods. Now with the addition of Newegg to it's repertoire of business affiliates, BitPay is receiving more credence as a leader in the march toward the legitimization of BitCoin as a secure digital payment system.
Eleven APIs have been added to the ProgrammableWeb directory under the Home Automation, Marketing, Payments, and Healthcare categories, among others. Featured today is an API for open source smarthome automation system Domoticz. Have a look at the new additions in this summary.