Privacy, use & software notices
Last updated: October 30, 2026
An independent chess project. AntChess is a personal hobby project created from a passion for chess and offered for chess study and enjoyment. AntChess is an independent project and is not affiliated with or endorsed by Chess.com. Chess.com trademarks belong to their respective owner.
What this site does
AntChess reviews completed chess games. You can paste a PGN or request public game records for a Chess.com username. The review runs in your browser using Stockfish and this site's own analysis logic. Evaluations and move labels are estimates for study, may be inaccurate, and are not official Chess.com evaluations or classifications.
Use analysis only after a game is over. Do not use an engine or this analysis during a live game or in any way that violates a chess platform's fair-play rules.
Chess.com data and trademarks
When you request games, your browser requests public game archive data from the Chess.com Published-Data API (PubAPI). The API is read-only and Chess.com documents serial access and response caching. This site does not ask for Chess.com passwords or authenticate with Chess.com. Imported PGNs are processed in your browser for analysis.
When an archived PGN contains clock comments, AntChess displays the remaining clock and computes time used per move in this browser from those comments and the PGN time-control header. Timing comes from the same public monthly archive records; it does not trigger a separate timing request.
Chess.com’s API is used only to retrieve public game records when a user chooses that import option. Game analysis is performed with Stockfish and this project’s own code; this project does not use Chess.com’s proprietary review engine or source code. If Chess.com has concerns about the project or its use of public data, the maintainer is willing to review them, make appropriate changes, disable the affected feature, or take the site offline.
Public availability does not mean every use is unrestricted. Chess.com publishes separate API guidance and User Agreement terms concerning User Game Activity, commercial use, derivative uses, and Chess.com visual identity. This notice is not permission from Chess.com and does not override its terms. Please review the PubAPI guidance, User Agreement, and Fair Play Policy.
Player Study
Player Study fetches your public monthly game archives from the Chess.com PubAPI in your browser, calculates statistics locally, and stores the fetched games and results in your browser's IndexedDB. Nothing from this study is sent to an AntChess server.
Information stored on your device
AntChess stores a cookie holding the Chess.com username; browser local storage for the current session, settings, game position and analysis; and IndexedDB for fetched monthly archives and Player Study results. These items stay in this browser. The Clear my data button on Player Study deletes the username cookie, the site's local storage entries and its IndexedDB archive. You can also clear site cookies and storage in your browser settings.
Pasted PGNs and engine analysis are processed in the browser; AntChess does not provide accounts or server-side analysis. Shared analysis URLs may include a move position, and a games URL can include a username. Google Fonts and Google AdSense may receive technical request information and handle it under their own privacy terms.
Advertising and cookies
AntChess may show ads to help cover domain and hosting costs. Advertising consent is handled by Google's consent message, which is shown to visitors in the EEA, UK and Switzerland. Google's message provides the available privacy choices and may provide a control to reopen those choices.
Anonymous usage counter
After a completed game analysis or a successfully loaded Player Study report, AntChess may count this browser once so the home page can show aggregate player and country totals. The counter uses a random ID stored in this browser and a country code; it counts browsers, not people. Separate browsers or devices count separately, and clearing this site's data removes the local ID so this browser may count again. Visitors in the EEA, UK and Switzerland are not counted.
The counter stores random IDs, aggregate totals and country codes. It does not store names, usernames, IP addresses, user-agent strings or other personal details. A short-lived keyed hash of an IP address is used only to enforce the counter's rate limit and expires after one minute.
Read How Google uses information from sites or apps that use its services. You can manage ad personalization through Google Ads Settings or aboutads.info.
Analytics
AntChess uses Vercel Analytics. It does not use Google Analytics or Speed Insights.
Open-source and third-party software
Opening names and ECO codes in the local opening book come from lichess-org/chess-openings, released under CC0 1.0. If the optional strong-game book is built, it uses a local file from the Lichess game database, whose database exports are also released under CC0 1.0. The generated opening data is bundled for local use; game files are not uploaded by AntChess.
Stockfish.js 18.0.8 is distributed under GPL-3.0. The corresponding upstream source is nmrugg/stockfish.js, commit 93c9945. The license text is available at /stockfish/Copying.txt; source information is at /stockfish/SOURCE.txt.
This application also uses third-party packages including React and React DOM (MIT), chess.js (BSD-2-Clause), react-chessboard and dnd-kit (MIT), clsx and tailwind-merge (MIT), GSAP (GSAP Standard License), and their dependencies. Their respective copyright and license terms continue to apply; package metadata and license files are included with their respective source distributions. See the GSAP Standard License.
The project creator reports that the move-classification PNG artwork was created for this project using generative AI tools; it was not supplied by Chess.com.
Contact
AntChess is maintained as a hobby project out of a passion for chess. If you encounter a problem or have a concern, please let us know. We will review your message and address it appropriately; where warranted, this may include changing or removing a feature, or temporarily or permanently taking the site offline.
We also welcome thoughtful feature suggestions and requests to remove content or functionality. Please contact us at contactantchess@proton.me. Thank you for visiting AntChess, and we hope you enjoy using it.