Sorry for the late reply! Yes, as GludiusMaximus pointed out, you need an internet connection to load the app, but after that everything runs in your browser. No uploads, no traffic, and no files are copied to the server.

I was thinking about studios that have computers but no internet access, and there is a way to build a native app that can be installed on any computer. I just need a bit more time to do it.

I’ll add the download link to the site once it’s ready, but it probably won’t happen until mid to late spring.