What are some alternatives?
When comparing Roost and Pusher Push Notifications API, you can also consider the following products
PushCrew - Push Notifications for Websites
Push Notification Preview - A simple tool for previewing push notification copy
OneSignal - Customer engagement platform used by 800K+ developers; the fastest and most reliable way to send push notifications.
iZooto - Engage your mobile and desktop web users with intelligent web push notifications.
PushPrime - Supercharge your website with push notifications
PushOwl - Re-engage website visitors with push notifications