There are a large number of authentication systems that might be used when working with web services.

For services which expect to use the current user account to authenticate, the UseDefaultCredential parameter may be used to pass authentication tokens without explicitly passing a username and password. A service that is integrated into an Active Directory domain, expecting to use Kerberos authentication, might be an example of such a service.

Implementation of authentication in REST-based web services varies enormously.

REST interfaces written to provide automation access tend to offer reasonably simple approaches to automation, often including basic authentication.

Interfaces written as an endpoint for other clients, for example the REST interface provided by Spotify, require complex client-implementation specific authentication and authorization exchanges. One of the most popular of these processes is OAuth.