I have a need to send a message from an Arduino to a Flutter app on a local WiFi network. I was thinking I could perhaps run a HTTP server on the mobile device and just make a GET/POST request from the Arduino, but I can't seem to find a http server plugin for Flutter which would run on a mobile device.

Any ideas how to accomplish this? I know I could use something like Firebase or Blynk, but it would require the devices to have Internet access, which I would want to avoid.