@W4GO Never believe a programmer; multiply their time estimates by at least a factor 3! 
In the end, it took me 3 hours to test and debug, but 1 minute Xflux updates work now and I published the new app version.
However, you will need to reload the web page with CtrlShiftR or clear the browser cache on your smartphone to see the updated version of the app. Otherwise, it takes one week for your browser to realise there is an updated version. You will know you have the latest version when you read the line Updated every minute for Xflux; 5 & 30 minutes for other values.
Please, also note that there is a 3 minute lag between the GOES satellite observation and NOAA publishing the Xflux value in JSON format. To be quicker, one would need to decode the proprietary GOES feed. I am not going to do that, but Python code contributions are always welcome. Anyhow, I assume my app is still quicker than any SMS and e-mail alerts. (Please, test.)
Moreover, their are occasionally small gaps in the satellite observations when the Earth or Moon is obscuring the satellite’s view to the Sun. This tend to happen around noon and midnight and especially around the equinoxes.
Matt, let us know how this works for you.