OAuth Protocol

In the World Wide Web, the client can be a web browser, and the server can be an application server.

However, there are more complex scenarios that involve more parties. One such scenario is when a server needs a client’s authorization to retrieve the client’s data from a different server. For example, this could happen when an e-mail application wants to retrieve the email accounts of your friends in a separate social media application in order to add them to your contacts list. OAuth is a protocol that allows this to happen in a secure way.