A demo App Engine server using https://w3c.github.io/push-api/ to send push messages to web browsers.
Live version: https://johnme-gcm.appspot.com/chat/
Currently requires Chrome 42+. As other browsers land support for the Push API, this repository will be updated, and should start working with Firefox etc.
See requirements.txt for instructions on installing dependencies, if you want to run your own copy on App Engine.