PubNub - PubNub is a real-time messaging system for web and mobile apps that can handle API for all platforms and push messages to any device anywhere in the world in a fraction of a second without having to worry about proxies, firewalls or mobile drop-offs.
Morpheus - Morpheus is integration software designed to help major cloud infrastructure work in harmony. For example, if a company has assets on both Google's and Amazon's cloud services, Morpheus helps bridge the gap to improve productivity.
Ably - Serious realtime infrastructure
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
Pusher - Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.
RightScale - RightScale enables organizations to easily deploy and manage business-critical applications across public, private and hybrid clouds.