Yes — every feature is free and there's no signup.
In your browser's LocalStorage. Nothing leaves your device unless you choose to share a link or export a file.
All three are supported from the Export section in the sidebar.
After the first load, the app continues to work without internet.
The Share button encodes your timetable into the URL hash, so the recipient gets the same schedule when they open it.
For now, one is autosaved. You can export each one as JSON and reimport later — multi-timetable support is on the roadmap.
The web app is fully mobile-responsive — add it to your home screen for an app-like experience.