Real UCI engines run on your server. Set the depth, time, number of lines, CPU threads, and engine memory, then review a game or analyze a single position.
How the review works
Each played move is compared with the engine's best candidate at the same position. When it isn't in the candidate list, a separate search evaluates it. Evaluations always use White's perspective.
We transform centipawn evaluation with 100 / (1 + exp(−cp / 300)). The drop in this value classifies inaccuracies (5+), mistakes (10+), and blunders (20+). Review accuracy is the average of 100 × exp(−drop / 20). This is a transparent local estimate, not Chess.com's score or a calibrated win prediction.
Best is the first engine candidate. Great marks a best move with a large gap over the second candidate. Book comes from a small local collection of opening lines. Missed win flags a lost winning advantage. We do not invent brilliant-move or estimated-rating claims.
Depth and time affect the results. Short searches can miss ideas. A partial review scores only the moves analyzed.
Connect Chess.com
Install the included browser extension, set this site's address, and enter your Chess.com username. Clicking Analysis or Game Review opens this site with the visible moves or the exact game link. Review completed games here.
Chrome / Edge: open the extensions page, turn on Developer mode, choose Load unpacked, and select the extension folder. Firefox: use the included Firefox build via about:debugging for temporary installation; permanent Firefox installation requires Mozilla signing.
Source code, installation help, backups, and extension instructions are in the download package. No Chess.com account password is needed.