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.
OptiMine - Disrupting the Marketing and Advertising Industry via Agile Marketing Attribution, Marketing Mix Modeling & Optimization
PushBots - Light SDK for mobile push notifications
NotifyVisitors - Cross Device Customer Engagement & Conversion Rate Optimisation Software
iZooto - Engage your mobile and desktop web users with intelligent web push notifications.
EmailOctopus - Email marketing for less, via Amazon SES