Android Question How B4J Server (backend) can send messages to mobile phone app?

[Xandoca]

Hi,

What is the best or common way to B4J Server (backend) send communication to mobile phone app?
For example: server send a message to one specific mobile phone.
I've read about MQTT, Serversocket/socket, push notification.
Real scenario is: server should know the "status" app (more than 300 clients [mobile phone]). If status is off, server will notify an administrator by email.
I think about the clients regularly send status to server but I'm more interested on "Server send the messagem to clients".

Thank you.

 

[amorosik]

Fcm is the only way to awake a sleeping smartphone
Mqtt is very useful to comunicate from pc to smartphone (fast and at no cost), but this must be awake and active
Then Fcm + Mqtt in my opinion is the best way

 

[Xandoca]

Fcm is the only way to awake a sleeping smartphone
Mqtt is very useful to comunicate from pc to smartphone (fast and at no cost), but this must be awake and active
Then Fcm + Mqtt in my opinion is the best way

Thank you @amorosik !!! That's exactly what I'm looking for. I will make some tests.