Cloud Sync is what an account adds on top of Guest Mode: your progress is saved to Tarc's backend (Supabase) and kept up to date across every device where you sign in.
If you used Guest Mode before creating an account, your local data isn't discarded — a merge step combines it with your new account on sign-up, so you keep progress made before you signed in.
It isn't a general-purpose offline-editing system — see Offline Mode for what is and isn't supported without an internet connection. Cloud Sync's job is specifically keeping your account data consistent across devices when you're online.
Sign in with the same account (same Google account or same email) on another device or browser, and your synced progress appears there — no separate export/import step needed.
Yes — Cloud Sync only applies to signed-in accounts; Guest Mode progress stays local to one device.
It's merged into your new account automatically, rather than being overwritten or lost.
Yes — signing in with the same account on both devices keeps XP, streak, completed lessons, and profile data consistent across them.