PushEngage - Personalized Browser Push Notifications.
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.
Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
Mixpanel - Mixpanel is the most advanced analytics platform in the world for mobile & web.
Gotify - a simple self-hosted server for sending and receiving messages
Pushy - Pushy is a reliable push notification gateway for time-sensitive, mission-critical apps.