I am creating an app to extract user's emails once they arrive at the uesr' Gmail account (automatically).
After reading Gmail API, I conclude that each extraction (of a Gmail) would require a user authorization through the Oauth 2.0 flow.
I am wondering if there is a way to extract an (G)email by providing an api_key (each gmail account would have its own api_key, obtained by gmail account user registering the app with Google)? The key is to extract (g)email without requiring manual authorizations by gmail account owners.