Pusher

Pusher is the category leader in delightful APIs for app developers building communication and collaboration features. Using its core product, Channels, developers can easily create interactive features such as in-app notifications, activity streams, chat, real-time dashboards and multi-user collaborative apps. They have over 250,000 developer customers across 170 countries. They’re used by everyone, from one-person operations to companies such as The New York Times, Mailchimp, Intercom and Draft Kings.