Google contacts API for CRUD

Hello Coders,

Currently i am working on MVC application. In my application, i have employee table, where application is maintaining employee details including name, contact number, email address etc. As per requirement i need to store these information on google contacts as well. Whenever CRUD operation is performed on employee table i need to do same CRUD operation on google contacts. I found Google Contacts API blog to do same, but i think this is more complex as compared to other API's. 

My queries are :

1. Should i call google contacts CRUD operation in background ?
2. What about OAuth ? Do i need to verify application only once or on every request ?
3. can i have source code ? or simple example to do CRUD operation on google contacts by calling API ?

Thank you.