There are four main participants in an OAuth 2.0 workflow: Resource Owner, Client, Authorization Server, and Resource Server. Using the OAuth 2.0 workflow, a resource owner that is a user or a system would like to authorize a client to access protected resources that can be accessed using an access token. A client asks for an access token from an authorization server. A client uses the access token and requests access from the resource server. A resource server validates the access token and returns the requested resource.