title: Mutual SSL authentication on Google App Engine
body: <p>I have an application where the client uses mutual SSL authentication through NGINX. So far, so good.</p>
  
  <p>However, I want to move my project to Google App Engine and I need to use the same approach to valid the client, or at least, forward the client certificate to be validate in the application.</p>
  
  <p>Is there some way to use mutual authentication on App Engine or other Google Cloud service?</p>
  
  <p>Regards!</p>