This client library written in Ruby allows developers build headers for the SendGrid SMTP API in Ruby. The SendGrid SMTP API allows developers to deliver custom handling instructions for email. SendGrid is an email application.
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.