Send notifications to your phone from any Bash or PowerShell script, or from your own app using PUT/POST requests, e.g. via curl on Linux or Invoke-WebRequest.

Ntfy is an Android client for https://ntfy.sh, a free and open source HTTP-based pub-sub service. You can subscribe to topics in this app, and then publish messages via a simple HTTP API.

Uses:
* Notify yourself when a long-running process is done
* Ping your phone when a backup has failed
* Alerts when someone logs into your server

Example:

$ curl -d "Your backup is done" ntfy.sh/mytopic

Find more examples and usage instructions here:
* Website: https://ntfy.sh
* GitHub (server): https://github.com/binwiederhier/ntfy
* GitHub (Android app): https://github.com/binwiederhier/ntfy-android