Google Identity Toolkit enables app and website makers to easily support multiple authentication options for their end users. The service currently supports password authentication in addition to federated sign in with Google, Facebook, Yahoo, Microsoft, Paypal, and AOL. Even non-technical developers are able to add future login options and migrate existing users with simple configuration changes.
These frontend and backend pieces together minimize the developer's burden of writing secure login code and maintaining different types of users. The login flow results in a unified user object representing the authenticated user and can begin a signed in session, enabling access and personalization as desired.
To see how your new app could function with Identity Toolkit, try our federated+password demonstration site.
To see how your existing app could transition to federated login, try our password only demonstration site. You would migrate to this flow first, then with only one non-technical step can transform to a federated+password flow (same demonstration site as above).
To improve the user experience, the toolkit supports an account chooser as shown below. In many cases it will enable a user to sign up on your site in 1-click by choosing one of the email addresses known by their browser. If no email addresses are known by the browser, the user sees your normal login screen.