Email Handling in ASP.NET Core -- 3

please imaging a user login a site. the user like the site so he send invitation his friends. in this case email addresses exist in his contacts. gmail contacts, facebook contacts, twitter contacts, instagram contacts. for example, in gmail case the site can get the user's grant and access token using "Google API authentication with OAuth 2" and get . and then get contacts using the access token and send invitation to the email addresses of the contacts .

Project ID: 19424007