Who uses OAuth 2.0?

In the previous section, we mentioned that OAuth 2.0 has become one of the most important protocols for applications and service providers today. But how important is it? Here is a short, non-exhaustive list of some of the biggest supporters of the OAuth 2.0 protocol, along with some of the capabilities that they provide:

• Google: You can leverage a multitude of Google's services by interacting with their APIs via OAuth 2.0
• Facebook: Facebook's social graph is accessed via OAuth 2.0 and allows users to do a tremendous amount of things, including posting to their wall and sending messages
• Instagram: Instagram allows you to access a user's feed and post comments and likes
• LinkedIn: Post comments, share links, and gather engagement statistics via the LinkedIn APIs
• Spotify: Query Spotify's massive music catalog and manage user's playlists using Spotify's APIs
• Foursquare: The Foursquare API lets you look up users and places from all over the world

There are many, many more companies that use and support the OAuth 2.0 protocol. This gives developers an enormous amount of power to create amazing applications that can leverage all of these world-class services.