Important: Versions 1 and 2 of the Google Contacts API have been officially deprecated as of April 20, 2012. They will continue to work as per our deprecation policy, but we encourage you to move to version 3.
The Contacts Data API allows client applications to view and update a user's contacts. Contacts are stored in the user's Google Account; most Google services have access to the contact list.
Your client application can use the Contacts Data API to create new contacts, edit or delete existing contacts, and query for contacts that match particular criteria.
To learn about the client library for a particular programming language, select the corresponding section. To learn more about the underlying protocol used by all the client libraries, select the Protocol section.
Each section of the guide covers the same material: how to get started and how to perform basic operations using a particular client library.