Firebase is a cloud-based messaging service that makes it easier for developers to send push notifications to users from their applications. It was acquired by Google in 2014 and could already send notifications to mobile device users from both Android and iOS applications and from Chrome apps, but now has increased reach and capability. It is now available to use, for free, on Chrome (on both desktop and mobile), Firefox (desktop and mobile) and Opera (mobile).
In terms of competition, Amazon Web Services offers a similar service called Simple Notification Service which sends SMS messages and is available in over 200 countries. Text messaging is traditionally more flexible than push notifications, but that is changing as both mobile and desktop operating systems are incorporating an increasingly rich experience surrounding notifications and how users can receive and interact with them. Text messaging is often also seen as more intrusive to a user, whereas a notification is more an expected behavior for an app. Notifications also provide the user with more options to block or tailor the notifications to their own preferences, either within the app or at a system level.
It is also expected that Firebase messaging will be enabled in future releases of Microsoft's Edge Browser on Windows 10 and the Samsung Browser.