Is it necessary for the controller to be active on the computer?

I am new using OpenRemote, I made my first program and downloaded it in the cell app, but when I close the CMD on my computer that synchronizes the localhost: 8688 / controller with the app, it stops working. Always has to be active cmd ?. How do I prevent this from happening?

That's a simple one to answer.

Yes, the CMD environment must stay active as it's running the OpenRemote Controller, which is the gateway your phone app is using to connect with your devices.

I assume you're using a Windows environment if you refer to CMD.

You could try running the batch file from the command line (or editing the desktop shortcut) so that it reads like this

{Your full path}/bin/openremote.bat run

That will start OpenRemote with minimal command window activity, so you can leave it minimised.

Good luck,