You can self host a Gotify server (single file executable, web interface), install the app, set it to connect to the server on the local network. Sending a mess

You can self host a Gotify server (single file executable, web interface), install the app, set it to connect to the server on the local network. Sending a message is as easy as a curl to the server. It will show up in the apps. https://gotify.net/ https://gotify.net/ https://github.com/gotify/android https://github.com/gotify/android The problem is that there is no iOS app. You could use the browser there but maybe ntfy would be a better fit (Android + iOS.)