Send push notification fcm


I am trying to send notifications using the firebase function and I have several problems!

First: How to put a badge?

Second: How to make a notification in back ground (when the application is off)

Third: How to make the notification in large (on android mobile …)

Thank you very much !

My Payload: 
        const payload = {
            "notification": {
                "title": "Follower",
                "body": "Une personne vous a suivi.",
                "priority" : "high"
            "data": {
                "badge": "1"

Here somethings has to be clear
In First If you need to show badge inside the application then you can us the Badge plugin

In Second You don’t need to handle the notification explicitly in background. Automatically android system takes care of it.

In Third: you can customize using scss folder with the badge plugin.