What we store.

Short version: the minimum to run your account, nothing sold, nothing used for ads.

In your account

• Your email address (to sign you in), and your name and picture if you sign in with Google.
• Your chess.com username, its public avatar and country, and whether you verified it.
• Your limits and daily game counts, once the extension syncs them.
• Your study progress: lines learned, reviews, goals, streaks and achievements, as the app moves to the site.
• Which games you reviewed each week (game ids only), to count Free reviews.
• Feedback you send from the app, with the page it came from, the app version, your theme, screen size and recent error messages, plus a screenshot if you attach one.
• Your plan, once Pro exists. Payments go through Stripe, which holds your card details. We never see them.

Not stored

• Your chess.com password. Luft never asks for it.
• Your games. They're public on chess.com and Luft reads them again when it needs them.
• Your browsing, or anything on chess.com beyond your username and game counts.

Error reports and usage

• When something breaks in the app, an error report goes to Sentry: what failed, the page (sign-in codes removed), your browser and your account id. Never your email or name.
• Usage analytics go to PostHog, on app pages only and only while "Share usage analytics" is on in your account: page views and a few actions like learning a line or solving a puzzle, tied to your account id. Session recordings, when on, hide everything you type. No cookies.
• The public pages, this one included, load none of it.
• To keep bots out, signing in and joining a shared board can run a Cloudflare Turnstile check. Cloudflare sees your browser and IP address for it; we only learn whether it passed.

Where

Accounts live in Supabase (Postgres with row level security: each account can only read its own rows). Analysis runs in your browser, so your games aren't sent anywhere to be analyzed.

Export and delete

On your account page, "Export my data" downloads everything we hold about you as one JSON file, and "Delete account" removes your account and every row tied to it, right away.

Contact

Questions about your data: write to hello@lufthq.com.