How do I implement authentication and authorization when using the Google Indexing API?

Authentication is handled using OAuth 2.0. You'll need to create a project in the Google Cloud Console, enable the Indexing API, and obtain credentials (client ID and client secret). These credentials are used to authenticate your requests. Authorization requires ensuring the application has the necessary scopes granted to access the Indexing API. Consult the OAuth 2.0 documentation for details on setting up authentication flow.