Chrome Push API server + clientside. Where can I get a full tutorial?

Question

Google

Good afternoon.
I've already spent a couple of hours on this question. Found how to send on the client via JS. Created a project in Google Developers. Made Credentials Auth Key. Dug in libs. I picked a lot of things, except for the server part of this whole process. There are several services that are ready to send push for me for n money. But this is not our method.
For example, there is a service https://jeapie.com/ru/showcase2/
I am interested in the server part with personalized notifications. Those. sending notifications when the browser is closed. Now I just can’t understand how a channel is allocated for a specific user, where to send all this stuff and in what format (I found JSON for Android and iOS).
Mb somebody faced and is ready to share the information.
Thanks in advance for your replies.

Answer 1

https://developers.google.com/web/progressive-web-apps
https://developers.google.com/web/updates/2015/03/...