As of late August, 2016, Stream has officially opened a Firehose to its real-time platform, allowing users to listen to all feed changes via Amazon SQS or webhooks. The Firehose is an addition to the existing websocket framework and was put in place to allow for speed improvements in applications where real-time aspects were important to their core functionality (games, chat, etc.).
We have a real-time infrastructure that can support round trip times of sub 500 millisecond between posting an activity and an activity showing up.
This blog post will get you up to speed on how to integrate the Firehose into your existing or new Stream application by walking you through the best practices for the Firehose setup process. At the end of this post, you will understand how to generate emails and/or push notifications using a serverless infrastructure for your application.