Automate is an android app with many automation features, including notifications (which can open dialogs of various kinds if desired). There is a "cloud send"

Automate is an android app with many automation features, including notifications (which can open dialogs of various kinds if desired). There is a "cloud send" with an API allowing you to send arbitrary data to your phone. Not affiliated, just a happy user. https://llamalab.com/automate/ https://llamalab.com/automate/