Privacy
The short version: your materials stay on your device until you sign in or share them. The details are below, with nothing left out.
Notes and boards
Everything you write, notes, boards and formulas, is stored in your browser in IndexedDB. While you are signed out it stays there and is never uploaded. Once you sign in, your workspaces are mirrored to Tuboard's cloud storage so the same material opens on another computer, and the access rules in the database mean only your account and the people you invited can read them.
Invited students
When you share a workspace by link, anyone holding that link can open and edit what is inside, and changes during a lesson travel over Tuboard's realtime channel so every participant sees them. Send the link only to the students it is meant for, and treat anything you put in a shared workspace as visible to them.
Handwriting recognition
When you box a handwritten formula on a board, that piece of the board travels to a model provider so it can come back as a formula you can edit. Nothing else from your boards or notes is sent anywhere. The request exists only as long as the answer takes. If you signed in with Google, the token is checked purely to count your daily limit, and the request goes through Tuboard's proxy on a shared key. If you supplied your own API key, it is kept in your browser, or in the system keychain on desktop, and the request goes to the provider straight from your device.
Accounts
Signing in with Google gives you an account identified by your email address. It exists so workspaces can sync, invite links can be verified, and the daily recognition limit can be counted. A student arriving through an invite signs in with Google as well. There is no separate Tuboard registration.
Analytics and cookies
There are no advertising pixels. If you agree, the site sends Google Analytics page views and clicks on the primary buttons, nothing else. Without your consent the analytics script is never loaded. The app itself does not use this analytics at all.