Writing a .service Bundle
When an application service is invoked, the application becomes active. There seems to be no way to avoid this. At best you can immediately hide the application, but there will still be a flicker as windows appear and disappear.
The second way: a .service bundle
If you want a service that is purely a background operation, you can create a standalone service that has no UI. It’s very simple once you know how, but I haven’t found a lot of help online, although some books discuss it and you can find examples on GitHub by searching for NSRegisterServicesProvider.
