The People API lets you list authenticated users' Contacts and retrieve profile information for authenticated users and their contacts.

For example, let's say the authenticated user, Jen, has Fabian and Ranjith in her private contacts. When your app calls people.connections.list to retrieve a list of her connections, Jen is presented with a consent screen asking to give the app access to the list. If Jen consents, the app retrieves a list containing Fabian and Ranjith (with a resource name for each person). The app can then call people.get, passing in a resource name, to get private contact and public profile data for each person.

A merged view of profile information

The profile information that the People API retrieves is merged from various sources, depending on the following conditions:

Source Condition
Public Google profile data Always.
Google Apps domain profile data The domain admin has enabled external contact and profile sharing of domain-scoped data.
The authenticated user's private profile information One of the profile scopes has been granted.
The authenticated user's contacts The contacts scope has been granted.

Get Ready to Use the People API Request Contacts and Profiles