and I’m also curious about Windows , for example i have Signal Desktop installed , do all notifications go through Microsoft servers ? what about other apps ?
On android this can be mitigated with unified push (if the app supports it) , is there any similar solution for other OSes ?
If applications use WNS (a lot do I believe), then yes:
For local notifications (“created on your machine”), I don’t think so, however this is just speculation. They are however stored in a local SQLite database (wpndatabase.db) in this folder: %LOCALAPPDATA%\Microsoft\Windows\Notifications\.
If you have OneDrive configured to sync AppData (not sure if this is even possible) or Phone Link (or any other Cross-Device sync) enabled they might be stored on Microsoft servers.
However, when browsing through event viewer, I noticed there is a policy in gpedit.msc to disable WNS (do so at your own risk) under Computer Configuration > Administrative Templates > Start Menu and Taskbar > Notifications > Turn off notification network usage:
This policy setting blocks applications from using the network to send notifications to update tiles, tile badges, toast, or raw notifications. This policy setting turns off the connection between Windows and the Windows Push Notification Service (WNS). This policy setting also stops applications from being able to poll application services to update tiles.
If you enable this policy setting, applications and system features will not be able receive notifications from the network from WNS or via notification polling APIs.