One of the limitations that I had to deal with when I switched to GrapheneOS originally was that there was no mechanism for push notifications without Google’s Firebase Cloud Messaging. I had a particular use case where I needed notifications and so I started using Gotify to get notifications from a stock Android phone (with Google) to my new phone running GrapheneOS. I’m now using ntfy, but the principle is the same.

Using Tasker:

Create a task:

Step 1 is of type HTTP request:

  • Method - POST
  • URL - URL to ntfy server (ntfy.sh or self-hosted instance) which includes the topic (e.g. https://ntfy.mydomain.tld/obscure-topic-name)
  • Headers 
    Title: %evtprm2
Priority: low
Tags: my,comma-delimited,tags
  • Body 
    %evtprm3

Step 2 (optional) is of type Flash for debugging

  • Text 
    Calling ntfy with the title %evtprm2 and message %par2

Create an event profile of type notification:

  • Owner Application - application I wanted notifications from, but you can select multiple or all
  • New Only - checked
  • Priority - normal

When the notification profile is active, set it to call the notification task. That’s it - every time a new notification for the selection app(s) arrives, it will send it to ntfy. Then just use the ntfy app on a different device to subscribe to that topic.