Privacy policy
Last updated: 3 November 2026
Who we are
Chess Coach is an independent service operated by Ignacio Soler (Spain), who is the data controller for the personal data described here. Contact: ignaciosolere@gmail.com.
What Chess Coach does
Chess Coach is a connector for AI assistants such as Claude and ChatGPT. When you ask it to, it downloads your public, finished games from Chess.com or Lichess using the username you give it, analyzes them with the Stockfish chess engine and returns the results to your assistant, together with an interactive board.
Data we collect
- Account data: when you connect Chess Coach you sign in through our sign-in provider, WorkOS, with your email (and password or one-time code) or with Google. WorkOS stores your email and, if you use Google, your name and Google account identifier. Our servers receive your account identifier and, when supplied in the verified sign-in token, your email address and its verification status. We use the verified email to recognize complimentary reviewer access; account responses can return it to your assistant when you ask about your account.
- Settings and usage linked to that identifier: the Chess.com or Lichess usernames you save, your preferred explanation level, your plan and how many analyses you use each day.
- Chess usernames and game references that you or your assistant send with each request.
- Public game data (moves, players, ratings, results, clocks) fetched from the public Chess.com and Lichess APIs.
- Analysis results, kept temporarily in server memory to avoid repeating work. They are not stored in a database.
- Technical logs: time, tool used, a pseudonymous account code, outcome and errors.
- Board diagnostics: the interactive board itself (not your AI assistant) sends diagnostics to our server through a tool named
board_event. Each event records the board action (tab opened, lesson opened, question asked, practice answer right or wrong, or a failure), the name and version of the app that shows the board, an error text of up to 200 characters and a pseudonymous account code. They never include game moves, positions or the text of your conversation. They are kept in our technical logs (up to 30 days) and, as board button events, in product analytics (up to 12 months). - Website analytics: on this website we measure pages visited, how you arrived (for example from a search engine or an AI assistant), clicks on buttons and links, time on page, scroll depth, device type, browser and errors, with PostHog. We do this without cookies or similar storage on your device: your IP address is only used to compute a daily, irreversible visitor code and is then discarded. If your browser sends Do Not Track or Global Privacy Control, nothing is measured.
- Product analytics linked to your account identifier: your account email, saved Chess.com or Lichess usernames, sign-up date, plan, tools used and their outcome (success, limit or error). A limited description of a tool request can include the chess username being queried, a public game reference, date filters and the number of games requested. We also measure buttons used on the interactive board (for example "Why?" or mistake practice), subscription and payment events (checkout started, subscription started, changed or cancelled, payments succeeded or failed, amount and currency) and visits to the My account page. These details are available in our private PostHog workspace to review account activity and troubleshoot problems. We do not send game moves, PGNs, positions, sign-in tokens or the text of your conversation with the AI assistant to analytics.
- My account page: if you sign in at My account, we set strictly necessary cookies that keep you signed in on that page only (a sign-in token that expires within minutes and a marker that lets the page sign you back in, kept for up to 90 days). They are not used for analytics or advertising and are deleted when you sign out.
- Payment data, only if you subscribe: your Stripe customer and subscription identifiers. Card details are entered on Stripe and never reach our servers.
We never ask for your Chess.com or Lichess password. We do not receive your conversation with your assistant: only the parameters of each request (for example a username, a game link or a position). The interactive board sends the position you are looking at to your assistant, not to us.
How we use it
To provide the service: find and analyze the games you ask for, remember your settings, apply the daily limits of your plan, process subscriptions, keep the service secure and fix errors. We review account-level activity to troubleshoot problems and understand how the connector is used, and use aggregated website and product analytics to improve the service. We may email the address of your Chess Coach account about your account and important changes to the service, such as your plan, a free trial or changes to our terms or this policy; we send no third-party advertising, and you can ask us to stop at any time by replying to any of these emails. Legal bases: performance of our contract with you (the service and your plan) and our legitimate interest in keeping the service secure, working and improving, measured in a privacy-preserving way.
What we do not do
We do not sell your data, show ads, share it for marketing or use your games or your data to train AI models.
Who we share it with
Only with the providers we need to run the service, under contract and for that purpose: Google Cloud (hosting, analysis and account data, EU region), WorkOS (sign-in), Stripe (payments), Netlify (this website), PostHog (analytics, EU cloud in Frankfurt) and, if you use it, Google sign-in. We query the public APIs of Chess.com and Lichess with the usernames and games you request. WorkOS and Stripe may process data in the United States under the European Commission's standard contractual clauses.
How long we keep it
- Account data, settings and plan: while your account is active, and deleted within 30 days after you ask us to delete it.
- Daily usage counters: up to 90 days.
- Technical logs: up to 30 days.
- Analytics events: up to 12 months, then deleted or kept only as aggregated statistics.
- Analysis results: only in memory, until the server restarts.
- Payment records: as long as tax law requires (in Spain, generally up to 6 years).
Children
Chess Coach is not directed at children under 13. If you are under the age of digital consent in your country (16 in some EU countries), use it only with your parent's or guardian's permission.
Your rights
You can ask for a copy of your data, its correction or deletion, or object to its use at any time by writing to ignaciosolere@gmail.com. We reply within 30 days. You can also disconnect Chess Coach from your assistant at any time. If you are in the EU, you can complain to your data protection authority (in Spain, the AEPD).
Changes
If we change this policy we will update the date at the top of this page.