    <input type="hidden"
                  name="id"
                  value="ARTICLE_UNIQUE_ID">
          <!--~
            Because there is no authentication for outgoing XHR calls from AMP email
            messages, all authentication should be done using access tokens. In a real-life
            scenario, this hidden input field should contain one such limited-use access token.
          ~-->
          <input type="hidden"
                  name="auth_token"
                  value="REPLACE_WITH_YOUR_