Effective date: October 14, 2026
Your games and positions
When you enter a Chess.com or Lichess username, your browser requests your recent public games directly from that site; our server is not involved. Games you paste, positions you set up and the engine analysis stay in your browser. The Stockfish engine runs on your device. We do not keep a history of the games you review.
Downloads (annotated PGN files) are created on your device without being uploaded. There are no player accounts: you can use every tool without signing in.
AI explanations
For your key mistakes, the review can ask an AI model to write a one- or two-sentence explanation. To do that, your browser sends our server the facts about that position only: the position (FEN), the move played, the engine's best line and the detected tactics. It does not send your username, the rest of the game or anything else about you.
Our server passes those facts to Anthropic (Claude API) and, only if Anthropic is unavailable and we have switched channels, to APIMart (an API provider that relays the same model). They process the request to return the explanation, under their own terms. Every answer is checked against the board before it is shown.
To enforce the daily free limit, your browser keeps a random device identifier in local storage (it contains nothing about you), and for each request we store a one-way hash of that identifier and your IP address, the date, the model, the number of tokens, the cost, the response time and whether the answer passed our check. These records are kept for up to 90 days (daily counters for 30 days) and are not used to identify you.
Share links
If you create a share link, the game's PGN and its review summary are stored so the link works. Share pages are not indexed by search engines and are deleted after 180 days.
Private administration
A private administrator signs in with Google to manage the Blog. The database (Cloudflare D1) stores the administrator account, settings, Blog content, share links and the AI request records described above.
Information received with a web request
Like any website, our hosting and security provider receives the information needed to deliver a page: the requested URL, time, browser and device details, IP address and security signals. Cloudflare provides hosting, delivery, security and our database (Cloudflare D1) and processes that information under its own terms.
Analytics
If you choose Allow analytics, Google Analytics 4 records anonymous usage of the site. If you choose Necessary only, Google Analytics is not loaded. Until you choose, nothing from Google is loaded. You can change your choice at any time with Analytics preferences at the bottom of every page.
Besides page views, only these events are sent: review_start, review_done (with the time taken and the engine depth), coach_note_shown (whether an AI or rule-based explanation was shown), coach_quota_hit, retry_move, share, pgn_download and second_game. They never contain your username, your games, positions or explanations.
Your analytics choice is saved in your browser's local storage.
Cookies
Without analytics consent the public pages set no cookies. With consent, Google Analytics sets its _ga cookies. The private administrator sign-in uses authentication cookies that only the site administrator receives.
Messages you send us
If you email support@chessanalysis.dev, we receive your message, your email address and anything you include. We use it only to reply and to fix reported problems.
Children
The site is not directed at children under 13 and does not ask visitors for personal details. We do not knowingly collect personal information from children under 13.
Advertising
Google AdSense ads are not currently shown on this site. If ads are added later, this policy will be updated first, and any required advertising consent controls will be in place before that processing starts.
Changes and contact
We will update this page and its effective date if the way the site handles information changes. Questions about this policy: support@chessanalysis.dev.