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.
Pusher Beams - Send push notifications programmatically at scale
Mixpanel - Mixpanel is the most advanced analytics platform in the world for mobile & web.
Snowball Smart Notifications - Get the notifications you want and none of the rest
Pushy - Pushy is a reliable push notification gateway for time-sensitive, mission-critical apps.
Engagespot - Engagespot is the easiest way to build your product's multi-channel notification infrastructure. Deliver In-App, Email, Push, SMS, WhatsApp and chat notifications from your app to your users with a single API.