How we compare chess bots
This page explains how we rank bots and where our bias could creep in. We are the team behind ChessHelper (chesshelper.ai), so you should know exactly how we keep that in check.
What we compare
For bots you play against, we look at five things: the range of strengths available and how finely you can set them; whether games are rated; training aids during the game, such as takebacks, hints and threat warnings; how human-like the play is; and cost and platform (web, mobile, offline). For review tools, we look at whether suggestions can be matched to your level, what analysis is shown and what it costs.
Where the facts come from
We use primary sources only: each company's own website and help center, published source code (for example, Lichess's open-source fishnet code for its Stockfish levels), official bot profiles and peer-reviewed research papers (for Maia). We note when a figure is the company's own claim, such as Chessiverse's description of its bots. We compared published features and pricing; we did not run timed test programs, and we do not publish test scores, star ratings or user reviews.
Chess accuracy
Every move, line and position on the site is checked for legality with a chess rules library, and every evaluation is from Stockfish at depth 18 or more. We round evaluations ("about a pawn and a half") because exact numbers change with depth and engine version.
The ChessHelper conflict of interest
ChessHelper is our product. We handle that in four ways. We disclose it on every page. We do not rank ChessHelper as a bot to play against, because it is not one; it appears as a companion for learning from bot games, the job it was built for. We name the products that beat it at other jobs. And we hold ChessHelper to the same sourcing rule as everyone else: its facts come from chesshelper.ai.
Updates
We review every page at least every six months, and sooner when a provider announces a change. Each page shows its published and updated date. Prices are given "as listed in" a stated month. If you spot something out of date, email contact@bestchessbot.com.