I would like to send a message to a Google Hangouts user from an application running in the Google Application Engine. I need something like the XMPP service that allows to comunicate with the deprecated Google Talk. Is it possible?
Thanks
Google sent out an email to existing developers about the XMPP service when Hangouts was released, essentially stating that no, the XMPP API for AppEngine won't interoperate with Hangouts.
They have not yet released any APIs that would allow external applications to send messages to Hangouts users. So as of the time of this post, it is not currently possible.
This may change in the future, but Google has not provided any guarantee that it will.