The Postmark Node.js SDK by Wildbit allows API interaction to implement email features into applications. Installation code included. References explain how to send an email and send a batch of messages.
Google Contacts API gives client applications access to a user’s contacts list where the application can create new contacts, update or delete existing ones, or query for contacts that match particular criteria. This tutorial explains how to implement the API in C# and ASP.NET with OAuth 2.0.
Taking advantage of APIs is a quick and inexpensive technique for a business so long as those APIs are available and remain constant. Changes happen to APIs all the time and this is the story of Stitch, a company that found a way to succeed, despite the uncertainties inherent to the API economy.