Last updated: July 4, 2026
Deepline (“we”, “us”) is an AI chess coaching service at deepline.coach. This policy explains what data we collect, how we use it, and who we share it with. We keep it plain and honest.
Account data: your name, email address, and a password hash (or your Google account profile if you sign in with Google).
Chess platform data: the Chess.com and Lichess usernames you give us, and the public games, ratings, and PGNs we import from those accounts.
Usage data: analysis results, coaching conversations, puzzle and training performance, your coach settings (creature, name, style), and the preferences you set within the Service.
Payment data: if you subscribe, our payment processor (Stripe) collects your card details directly. We never see or store your full card number — we only store a Stripe customer ID and your subscription status.
We use your data to provide game analysis and personalized coaching; generate your weakness profile, puzzles, and training; track your improvement; process your subscription; send service and (with your consent) progress emails; and improve the Service. We do not sell your personal data to anyone.
To explain your moves and answer your questions, the coach sends the relevant chess position and context to third-party AI providers (currently OpenAI and DeepSeek). Engine analysis (Stockfish) runs on our own infrastructure and in your browser. We do not send your name, email, or payment details to AI providers — only the chess context needed to generate a response.
We share data only with the service providers that make Deepline work, and only as needed:
• Stripe — payment processing and subscriptions.
• OpenAI & DeepSeek — generating coaching explanations (see §3).
• Chess.com & Lichess — we read your public games via their APIs.
• Analytics & hosting providers — product analytics and the infrastructure that runs the Service.
We do not sell or rent your personal data, and we do not share it for third-party advertising.
We use product analytics to understand how the Service is used and to improve it. We use essential cookies for authentication (session tokens). We do not use advertising or cross-site tracking cookies.
Your data is stored in a PostgreSQL database on managed cloud infrastructure located in the United States. Passwords are hashed with bcrypt. All data in transit is protected with HTTPS. No system is perfectly secure, but we take reasonable measures to protect your information.
We keep your account data while your account is active. You may request deletion of your account and associated data at any time by contacting us; we will delete it except where we're required to keep certain records (e.g. payment records for tax and accounting).
You have the right to access your personal data, request correction of inaccurate data, request deletion of your data, and export your data in a portable format. To exercise any of these, contact us at the address below.
Deepline is not directed to children under 13, and we do not knowingly collect personal data from anyone under 13. If you are between 13 and 18, please use the Service only with a parent or guardian's permission. If you believe a child under 13 has given us personal data, contact us and we will delete it.
We may update this policy as the Service evolves. We will update the date above and, for material changes, notify you by email or in-app.
For privacy questions or to exercise your rights, contact matthewma1522@gmail.com.