Privacy
Last updated July 16, 2026 · The short, honest version.
What we store
Your training progress (repertoires, review history, ratings, preferences) lives in your browser's local storage. If you create an account, the same data is synced to our database (hosted on Supabase) along with your email address, so your progress can follow you across devices. We don't collect names, addresses, or anything we don't need to run the trainer.
Sign-in
Accounts use email + password or Google sign-in, handled by Supabase Auth. With Google sign-in we receive your email address from Google; we never see your Google password.
Advertising
The free version of ChessReflex shows ads served by Google AdSense. Google and its partners may use cookies and similar technologies to personalize ads based on your visits to this and other sites. You can control ad personalization at adssettings.google.com, and read Google's policy at policies.google.com/technologies/ads. ChessReflex Pro removes ads entirely.
Third-party services
Training data may query the public Lichess opening database (positions only, never your identity). Payments, when available, are processed by Stripe — card details go to Stripe, never to us. The site is hosted on Vercel, which keeps standard server logs.
Your data, your call
You can use ChessReflex without an account, entirely locally. If you have an account and want it and its data deleted, email us and we'll remove it. Local data can be cleared anytime from your browser settings.