OmniAuth is an open-source software library for web applications that provides a unified authentication system across multiple websites and services. It was created by Intridea Inc. as a solution to the problem of authentication across multiple websites and services. OmniAuth simplifies the authentication process by providing a single sign-on service that allows users to log in to multiple websites and services with a single set of credentials. It supports authentication via a variety of popular services including Facebook, Twitter, LinkedIn, Google, and GitHub, among others. Additionally, OmniAuth also supports authentication via custom user databases and other authentication systems. It provides a secure and flexible system for user authentication across multiple websites and services, and is easy to integrate into most web applications.
Discontinued from http://stormpath.com/"Stormpath has joined forces with Okta. The Stormpath API will be shut down on 8/17/2017 at noon PST." Joined http://alternativeapp.info/software/okta/