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.
Webpushr - World most trusted web push notification platform. All browsers (Safari, Chrome, IE, Firefox, etc.
Firebase - Firebase is a cloud service designed to power real-time, collaborative applications for mobile and web.
Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
Braze - Braze is an engagement platform that empowers growth by helping marketing teams to build customer loyalty through mobile, omni channel customer experiences.
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.