cross-posted from: https://lemmy.world/post/17087912
Protonmail relies solely on Firebase for receiving notifications on Android. While UniversalPush support is probably in the works, it may take some time until users on ROMs without GSF get built-in notifications.
For those that already use ntfy.sh as a push provider for other apps, https://github.com/0ranki/hydroxide-push is a solution to get push notifications of new mail in Inbox.
The service requires a Linux box to run on, and can be deployed as a container or by running the provided binary. Building from source is of course also an option.
The service is a stripped down version of Hydroxide, the FOSS Protonmail Bridge alternative. There are no ports exposed, all communication is outwards. Communications to Proton servers use the Proton API. The service only receives events from Proton servers, and if the event is incoming mail, a notification is sent to a ntfy.sh server and topic of your choice. Other types of events are simply disregarded, and no other processing is done. The sent push event does not contain any detailed information.
EDIT: Starting from version v0.28.8-push7 the daemon supports HTTP basic auth for the push endpoint.
Disclaimer: I'm the author. All of the work is thanks to https://github.com/emersion/hydroxide, I've merely mutilized the great upstream project of most features for a single purpose. Issues, comments and pull requests are welcome!
IMAP only works with paid accounts
It only works through the Proton Mail Bridge application, which is only available for desktop. That's because Proton's end-to-end encryption makes it impossible to access your emails while they are on Proton's servers via IMAP. They would need to be decrypted on the server, but that would make the entire encryption pointless. The Proton Mail Bridge connects to the server, downloads the encrypted data, decrypts it locally on your PC and locally exposes an IMAP server, which contains your decrypted messages.