Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
Pusher Beams - Send push notifications programmatically at scale
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.
Parse - Build applications faster with object and file storage, user authentication, push notifications, dashboard and more out of the box.
PushOwl - Re-engage website visitors with push notifications