CHESS ASSISTANT FOR CHESS.COM — STOCKFISH 19
TERMS OF SERVICE
Last updated: 21 September 2026

1. THE SERVICE
Chess Assistant for Chess.com — Stockfish 19 is a browser extension that analyses chess positions with a copy of the Stockfish 19
engine bundled inside the extension. The analysis runs on your device. It is built specifically for
Chess.com and does not support other chess websites or desktop chess applications.

2. YOUR ACCOUNT
An account is required to use the assistant. You are responsible for keeping your password confidential
and for activity carried out under your account.

3. FREE TRIAL AND PRO
New accounts receive 250 free assistant moves. Pro is offered as a monthly subscription of EUR 4.99,
billed through Stripe, and can be cancelled at any time in the billing portal. Cancelling stops future
billing; access continues until the end of the period already paid for. Payment problems, cancellations
and expiries are reflected in the app from the state reported by Stripe.

4. ACCEPTABLE USE AND FAIR PLAY
Chess Assistant is intended for chess analysis, study and training. Users are responsible for complying
with the rules of Chess.com and of any competition or game in which they participate. Do not use engine
assistance in games where external assistance is prohibited. You are solely responsible for how you use
the analysis; the extension does not prevent any particular use, and no such guarantee is given.

5. THIRD-PARTY COMPONENTS AND TRADEMARKS
The extension includes Stockfish 19, an open-source chess engine distributed under the GNU General
Public License (GPL). Stockfish is developed by the Stockfish project and its contributors; it is not
developed, owned or endorsed by us. The required licence notices ship with the extension
(LICENSE-Stockfish.txt) and the engine source is available from the Stockfish project. Chess.com is a
trademark of its owner. This product is an independent third-party product and is not affiliated with,
sponsored by or endorsed by Chess.com or by the Stockfish project, and it is not an official Chess.com
product.

6. NO WARRANTY
The service is provided "as is", without warranties of any kind. Engine output is informational and may
be incomplete or wrong; it is not chess advice and no result is guaranteed.

7. LIMITATION OF LIABILITY
To the extent permitted by law, we are not liable for indirect or consequential losses, or for any loss
arising from your use of the extension or from your breach of any platform's rules.

8. CHANGES
We may update these terms; the current version is always available at this address.

9. CONTACT
gratzmvm@gmail.com