Pusher Beams - Send push notifications programmatically at scale
Amio Messaging SDK - Develop for multiple messengers using JavaScript
Pusher - Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.
Slack RTM API - Slack's Real Time Messaging API
Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
Location SMS - Location SMS is an application that allows the users to locate themselves by sending a simple text ‘Where are you?’ to the phone.