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.
Developers can often miss an important aspect of API development - scaling the API. To scale the API, you must look into offloading the administrative functions of multiple APIs in their apps. Scaling of the API at the design phase is crucial to the success of API adoption in the long run.