Ok after a few days of testing:
I'm pretty close to giving up and moving to another forum software... which would be a real shame since NodeBB offers everything else that I need and I wrote an LDAP plugin.
@meredrica notifications will only work if the page is open and connected to the internet. We don't have a serviceworker or anything like that for delivering push notifications.
Chat messages don't create a notification for each message received (to avoid notification spam) , instead only creating a notification after a set delay after the last message received, if it isn't read in time. They should produce a sound every time, though. If this is not the case, please open a GitHub issue.
Potentially there's a use case for a service worker to check for notifications, perhaps that's something we can look into.
On the sounds front, however, I'm a little on the fence about whether we should keep them. Not many apps use sounds, though I think there are more than a few people using NodeBB who would appreciate us keeping them around.
That said, I think we'd need some new sound assets 
@julian I think it would be a good idea to implement the worker. Maybe add it to the notification plugin? Or maybe a web worker, I'm not sure if that wouldn't be better.
Or maybe just a good old Javascript timer would do the trick.
Service workers can become very complicated and if you have bugs in them they are very hard to get rid of. I would not use them if you don't want to have offline functionality.
@meredrica I don't think there's an instance where a timer or webworker would stay alive when a websockets connection wouldn't. Depending on how often we want to poll, opening a new connection periodically could be more expensive than just keeping the socket connection open.
@meredrica what are you planning on writing? A serviceworker?
Hi,
I'm searching for a forum software with push notification support which works with closed browser.
That is possible with web push api and service worker as shown here:
That example isn't pinned to FCM, MCS or WNS and it used the push service based on the browser / device.
If the plugin is still compatible it should be added a service worker to get offline / closed browser notifications working.
IMO it's a feature for a separate plugin - not this one. This plugin, as the description suggests, is using Notification API, and not Push API.
A Push API-based notification plugin would be great, but it's not just an upgrade to this one as Push API works in fundamentally different way by using a service worker.
