An account stores your email address, an optional name, and the list of instances you have connected — their names, when each was last seen, and the health summary each one last reported. Nothing inside an instance is stored here: flows, node code, secrets and measurements stay on the machine that runs them and only pass through this site while you are looking at them.
An account is entirely optional. A self-hosted instance works offline with no account and no connection to this site; remote access is something you switch on deliberately, and switching it off on the machine ends it immediately.
We use self-hosted, cookieless analytics to count page views. No cross-site tracking, no advertising identifiers, and URLs are stripped of everything but campaign parameters before they are recorded. Pages that can carry a single-use token in their address — email verification, password reset — and anything under an instance are excluded entirely.
From Settings you can download everything this site holds about you as JSON, see and end your active sessions, and delete your account — which removes it and every instance registration with it.