Push notifications from Web server to android application

Hello to everyone who is viewing this question. I think this question might be quite abstract, but I couldn't find the correct answer by googling.

I am trying to make an application like Starbucks Siren-Order.

Our android applications are made in Android-Java, and we are also developing a web-server which is also
written in Java, using Spring-MVC.

Once a customer makes an order using this application(which is for customers), I want to make push notifications appear in Store-Owner-Application. I was thinking about using WebSocket, but is Firebase a great alternative for websocket in this case? I never used neither WebSocket or Firebase before.
Just asking for some tips and advice. Thank you

in simple cases, Firebase is a much better alternative to implementing it yourself using WebSocket.

That's because Firebase already has a battery draining constantly open socket to handle its notifications, and since most apps use it rather than creating a new socket, it helps conserve battery and other resources.

There are a few exceptions though..
Firebase isn't perfect, it allows sending messages to the client most of the time, and in some cases, your notification will be delayed, or won't get delivered at all.
For example:

1. If the battery is low
2. if the device received many push notifications recently

If you need a simple 99% solution to sending push notifications that is easy to implement and won't waste battery - Go with Firebase.

If you have to have full control over your notifications and need them delivered all the time, as soon as possible, consider implementing it yourself.