...Use Application Default Credentials when you use a single identity for all users in your application. Especially useful for applications running on Google Cloud. Application Default Credentials also support workload identity federation to access Google Cloud resources from non-Google Cloud platforms. Use JWT when you are using a single identity for all users. Especially useful for server->server or server->API communication. Use workload identity federation to access Google Cloud resources from Amazon Web Services (AWS), Microsoft Azure or any identity provider that supports OpenID Connect (OIDC). ...