Chessist

Live Stockfish evaluation for Chess.com and Lichess — a desktop app + browser extension.

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What it is

Two parts working together:

• Chessist desktop app (Electron + React) — runs native Stockfish, owns all settings, shows live evaluation, and (optionally) draws a transparent, screen-capture-invisible overlay on the board.
• Chessist browser extension — reads the board on chess.com / lichess.org, sends positions to the app, draws in-page arrows, and plays auto-moves.

Windows 10/11. The transparent overlay is Windows-only.

Features

• Native Stockfish — one persistent engine per session; the transposition table is reused across moves (reset only on a new game) with a large hash and multi-threading for fast, deepening analysis.
• Three render modes — Overlay (transparent native window on the board), In-page (arrows drawn on the chess site), or App (the desktop window draws its own board + best-move arrows).
• Live board + eval in the app — score, depth, best move, kNPS, and a board rendered from the current position (greys out and reports "Disconnected" when no game is active).
• Auto-move with human-like timing, best/opponent/alternative arrows, player-color perspective, and win/loss balancing — all configured in the app.
• No setup.bat, no Python — the app downloads Stockfish on first run; the extension is a pure WebSocket client and the app guides loading it.

Install

Prebuilt installers will land on the Releases page. Until then, install from source — one click builds and installs it.

Requirements: Node 20+ and the .NET SDK 8 (used to build the overlay).

1. Get the code — clone it (recommended; enables in-app auto-update):

   git clone https://github.com/imluri/Chessist.git

   …or download the ZIP from the repo / a release and extract it.
2. Double-click install.bat. It requests administrator rights (one UAC prompt — needed to build the installer), checks Node/.NET, installs dependencies and the overlay, then builds the Windows installer (npm run dist) and runs it. Chessist installs and launches automatically.
   • If the installer build can't run on your machine, it falls back to a portable Chessist shortcut in the project folder — launch from there and keep the folder where it is.
3. First launch downloads Stockfish — watch the Setup tab.
4. On the Setup tab, follow the Browser extension card: it reveals the bundled extension folder and walks you through chrome://extensions → Developer mode → Load unpacked. Works on any Chromium browser — Chrome, Brave, or Edge.
5. Open a game on chess.com or lichess.org. The board and evaluation appear in the app; choose your render mode and tweak settings via the gear (Settings → Game / Engine).

Updating: the About tab checks GitHub for new versions. A git clone updates in place (stable = release tags, beta = every commit on main); a ZIP install gets a one-click link to the latest release.

Using the app

• Evaluation — the live board, score, and best-move arrow (one purple arrow by default; enable Alternative arrows for the yellow/red lines).
• Settings (gear, or the sidebar item) — a modal with Game (depth, render mode, player color, arrows, auto-move + timing, behavior, win/loss balance) and Engine (skill, ELO, threads, hash).
• Setup — Stockfish / Overlay / Extension status, each in its own card, plus a re-download button.

The extension popup only shows a connectivity dot — everything is configured in the desktop app.

Develop

Requirements: Node 20+, .NET SDK 8 (only to build the C# overlay).

npm install
npm run build:overlay     # builds the C# overlay helper (overlay/bin/Release/net48)
npm run dev               # Vite + Electron

Build an installer: npm run dist (output in release/). CI builds the overlay + installer on a v*.*.* tag.

Project structure

Chessist/
├── electron/      # Electron main: Stockfish engine, WebSocket server, overlay driver, IPC
├── src/           # React renderer (sidebar, Evaluation, Settings modal, board, controls)
├── overlay/       # C# overlay helper — transparent, capture-invisible window (stdin-driven)
├── extension/     # browser extension (load unpacked)
├── scripts/       # dev helpers (build-overlay.ps1)
└── build/         # app / installer icon

Credits

Created by imluri. Powered by Stockfish (GPL, downloaded at first run). MIT licensed (app + extension).