Making HTTPS requests using a provided x509 certif

Question

I'm interested if Google App Engine provides a way to use a X.509 Certificate to create a HTTPS connection (the server where I have to connect provides the public certificate - to encrypt data that I send and the private key to decrypt the data received from that server).

According to this post https://groups.google.com/forum/?fromgroups#!topic/google-appengine-python/C9RSDGeIraE it's not possible but 3 years passed since this answer was posted.

Answer 1

SSL client certificates are not currently supported. The feature request is here.

Answer 2

AppEngine has the ability to work with SSL certificate on your custom domain, that means the you can assign a certificate to a domain that is running on the AppEngine.
You cannot AFAIK make a request and provide a custom certificate per request.

Documentation on AppEngine SSL.