Send user specific web notification

Question

Is it possible to send a user specific web push notification using Safari, Chrome, and Firefox?

I am doing research for a website that requires live notifications to be sent to users. For example, if a user enters into a fantasy basketball draft, they will receive a push notification on their Mac or Windows laptop.

I know that Safari, Chrome, and Firefox give developers the resources that they need in order to send notifications to all users that are registered for notifications. What I'm wondering is if using the same methods it would be possible to send specific notifications to specific users.

Safari: https://developer.apple.com/notifications/safari-push-notifications/

Chrome: https://developer.chrome.com/apps/cloudMessaging

Firefox: https://developer.mozilla.org/en-US/docs/WebAPI/Using_Web_Notifications

Are there any services out there that would do this for each browser, similar to Parse (https://parse.com/tutorials/ios-push-notifications)?

Answer 1

Partial answer, quoting Google Cloud Messaging docs you linked:

Similar to an email address, the channel ID is used to identify and send messages to a specific user of your app or extension. Your app or extension needs to send this value to its application server so that the server can trigger push messages back.