OneSignal - Customer engagement platform used by over 1 million developers and marketers; the fastest and most reliable way to send mobile and web push notifications, in-app messages, emails, and SMS.
Mailshake - Mailshake lets you build your professional network through a smart and intuitive approach to cold emailing.
Warply - A mobile marketing toolbox that powers up monetization, loyalty and engagement.
Pusher Beams - Send push notifications programmatically at scale
PushBots - Light SDK for mobile push notifications
SashiDo.io - SashiDo is the Parse Alternative for busy people.