Google OpenID API

The Google OpenID API lets third-party web sites and applications let visitors sign in using their Google user accounts. The OpenID standard allows users to nor have to set up separate login accounts for different web sites, and conversely, frees web site developers from the task of managing login information and security measures. OpenID achieves this goal by providing a framework in which users can establish an account with an OpenID provider, such as Google, and use that account to sign into any web site that accepts OpenIDs. This page describes how to enable a web site or application to accept a Google user account for federated login.


Google OpenID: Highlights

Summary
OpenID login for Google account users

Category
Security

Tags
OpenID security identity

Protocols
REST

Data Formats
XML
API home
http://code.google.com/apis/accounts/docs/OpenID.html

Google Plus Api

Google Plus is a service to share links, photos and other content. The Google Plus API allows developers to access publicly-available Google Plus content, including user information and publicly shared items.

Google Plus: Highlights

Summary
Content sharing service

Category
Social

Tags
microblogging social

Protocols
REST

Data Formats
JSON

API home
https://developers.google.com/+/api/