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How cheating is detected in online chess
In online chess, cheating almost always means using a chess engine or other help during a game. It is detected by comparing moves with what an engine would suggest and by watching how accuracy and thinking time behave over many games, and doubtful cases are reviewed by a person. No signal is proof on its own, which is why several are combined.
Updated October 28, 2026 · 2 min read
What counts as cheating
It is not only about engines. These are the most common forms:
- Using a chess engine, in another tab, on another device or with an extension, to choose the moves.
- Getting help from another person during the game.
- Agreeing results with an opponent, for example passing stakes between your own accounts or friends' accounts.
- Running several accounts to abuse the platform.
How an engine gives itself away
An engine plays differently from a person, and those differences leave traces:
- A very high match with the engine's moves, game after game and also in complex positions.
- Accuracy far above what is expected for the player's ELO.
- Thinking times that are too even, similar on easy and difficult moves.
- A sudden, sustained jump in level with no reasonable explanation.
Why one game proves nothing
A good player also finds very accurate moves, and a short game has few positions to analyse. What is revealing is the pattern across many games: a person makes mistakes and hesitates like a person, while someone using an engine keeps an accuracy and a rhythm that do not change. That is why several signals are compared and nobody is penalised for a single move.
How EonChess protects games with a stake
Every game with a stake is analysed with Stockfish, comparing the accuracy and timing of each move with normal human play. If an account's level makes an impossible jump, an alert is raised and its withdrawals are frozen until it is reviewed.
A person reviews every suspicious case. Once cheating is confirmed, the account is permanently blocked and the affected opponents get their money back. You can see last month's figures on the fair play page.
What to do if you suspect an opponent
If you think the result of a game was not clean, open a dispute from the game itself. The team reviews it and, if accepted, the game is cancelled and both players get their stake back. For anything else, write to support.
How to play so you are not flagged without reason
Playing very well is not cheating, and the analysis looks at patterns, not isolated moves. Even so, avoid anything that could look like it: do not open analysis boards or engines while you play, do not share your account or your device and use a single account. To improve without risk, practice for free against the computer and review your games afterwards.
For adults aged 18 and over only. Games with a stake may be restricted in some countries.
Still have questions? Check the frequently asked questions or write to support.