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
Webpushr - World most trusted web push notification platform. All browsers (Safari, Chrome, IE, Firefox, etc.
Magnify - Push out beautiful website announcements in 10 seconds.
PushEngage - Personalized Browser Push Notifications.
Push Notification Preview - A simple tool for previewing push notification copy