Privacy Policy

Last updated: September 2, 2026

DejaChess is built and operated by OctoPanther LLC. The short version: we collect the minimum needed to run the service, your game analysis happens on your own device, and we don't sell your data or run ads.

What we collect

• Account details. Your email address, via email/password signup or Google sign-in. If you sign in with Google we receive your email and basic profile info; we never see your Google password.
• Chess games. When you enter a Chess.com or Lichess username, we fetch games that those platforms already make publicly available. Games you choose to save are stored with your account, including the moves and player usernames that appear in them.
• Training data. The puzzles generated from your games, your answers, and your spaced-repetition schedule and stats.
• Feedback. If you send a note from the app, we store the message, the type you picked (bug, idea, or other), the page you were on, and your account email so we can follow up.
• Usage analytics. We use PostHog to understand which features are used and whether people keep improving — things like “a drill session was completed” or “an import ran.” This never includes your games or moves, and we don't use it for advertising.

That's it. DejaChess is free, so we never ask for payment details. We show no ads and never sell your data.

Where analysis happens

Stockfish runs in your browser, on your device. Your games are not sent to our servers for analysis — only the games and puzzles you choose to save are stored, so you can pick up your training on any device.

Cookies and storage

We use cookies to keep you signed in, and PostHog stores a random analytics identifier in your browser. Preferences like your theme and board colors are stored locally in your browser and never leave it.

Third parties

We rely on a few services to operate: Supabase (account authentication and database hosting), Google (optional sign-in), PostHog (product analytics), and the public Chess.com and Lichess APIs (game import). Donations are handled entirely by Ko-fi on their site. Each operates under its own privacy policy. We don't sell or share your data with anyone for marketing.

Your data, your call

You can unlink a Chess.com or Lichess account in the app at any time. To delete saved games, puzzles, and feedback, or your entire account and everything attached to it, contact us and we'll take care of it promptly.

Children

DejaChess is not directed at children under 13, and we don't knowingly collect their data.

Changes

If this policy changes, we'll update this page and the date at the top. Material changes will be called out in the app.

Contact

Questions or deletion requests: [email protected]