Introduction OAuth 2.0 is creating a lot of hype in the web service and software industry around the globe. And we often hear many IT products and services adapting to it. Simply put, "OAuth 2.0 is a protocol that allows distinct parties to share information and resources in a secure & reliable manner. " - Charles Bihis . (2015). Mastering OAuth 2.0 Now a days web applications are used very widely for almost every task. But it is difficult to remember separate credentials to each and every application. This is the basic problem OAuth tries to address. Best example is where Instagram allows you to login to Instagram using your Facebook account. This feature is powered by OAuth Protocol. Before diving deeper into OAuth 2.0 it is important to understand what the following keywords mean. Authentication - validating if the person is who he says he is. Authorization - what actions a person is allowed to ...