The Help Scout Ruby Library by Hector Ramos in beta stage helps to access the API features of fetching users, mailboxes, customers, and conversations. API required available at http://developer.helpscout.net/
The Streak API integrates its client relationship management (CRM) platform into other applications like MailChimps and Wufoo. The API's webpage reveals that it requires an API key and uses HTTP Basic Auth. The request format supports Create, retrieve, update, and delete (CRUD) with response in JSON. The purpose of the API is to manage CRM relationships through your application.
As a developer, you can figure out how to make your program connect to Facebook, Twitter, SMS, and Email. Or you can use the Embarke API and connect just to Embarke, a messaging platform that connects you to them all. You can skip learning the specifics of how to connect to each of them. The REST API's website has a five minute tutorial video on how to use this gateway to its developer tools for social communications.