What do you need to alert RealTime users?

Question

Socket.io

I read https://laravel.com/docs/5.4/broadcasting And I don’t understand, I need to change the html block for the user, by event (If new content comes to the database)
+ There are a lot of groups (sections) on the site and I need to let the user subscribe to event, if there is new information in the group, notify the user by browser, even if the site is closed.
What is needed for this if you use the websocket.io driver :
Laravel + websocket.io ?
Laravel + node js + websocket.io
Is laravel-echo-server needed? You can’t find normal documentation, since every half a year everything changes and for 2017 I didn’t find anything. If I use the Redis
driver , are there manuals with it for my task?
All the examples that I found are for older versions of Laravel, and after studying, I realized that they do not fit under 5.4.
What should I choose for my task, given that users from 50,000 and most need to be notified several times a day.
Addition:
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One friend from the toaster https://toster.ru/user/MarcusAurelius says:

Socket.io is not needed for anything. Check out this websocket example: https://github.com/HowProgrammingWorks/WebsocketChat

How to be in 2017? All the examples that I found in 2015-2016...

Answer 1

Ideal without third-party services - https://opensource.mail.ru/Centrifugo

Answer 2

I did this:
Laravel > Redis > Node > socket.io
Laravel writes to the radish, the node grabs the message from the radish and sends it to the clients.
Example .

Answer 3

As an option, write a service on nodejs + socket.io that will send notifications.

Answer 4

https://onesignal.com/