# Lumichess

> Free chess improvement platform. Analyze games, solve puzzles, learn openings, and track your progress — all running locally in your browser.

## What is Lumichess?

Lumichess is a free, browser-based chess improvement platform. All analysis runs client-side using Stockfish 17 (WebAssembly) — no server costs, no data sent to any server, no account required to start.

## URL

https://lumichess.com

## Key Features

- **Game Analysis**: Paste any PGN or import from Chess.com/Lichess. Stockfish 17 analyzes every move at depth 18. Get accuracy scores, move classifications (brilliant, great, best, good, inaccuracy, mistake, blunder), and natural language commentary explaining why each move was good or bad.
- **5 Million Puzzles**: Rated puzzle training with Glicko-2 rating system. Includes daily puzzles, timed puzzle storm, and learn-from-mistakes mode that replays your errors.
- **200 Interactive Lessons**: Free structured curriculum from beginner to expert (4 levels, 25 modules). Board-interactive tasks — not just multiple choice.
- **Opening Database**: Lichess opening explorer integration, personal game position search, game annotations with NAG symbols, PGN export.
- **Profile Reports**: Import your Chess.com or Lichess profile for deep statistical analysis — accuracy trends, opening performance, piece usage, improvement recommendations.
- **Play vs Bots**: 15 bot opponents from beginner (200 Elo) to grandmaster (2800 Elo).
- **Chess Monitor**: Track your stats across Chess.com and Lichess — games, openings, opponents, rating history, activity patterns.

## How is Lumichess different from Chess.com or Lichess?

| Feature | Chess.com | Lichess | Lumichess |
|---------|-----------|---------|-----------|
| Game analysis | 1 free/day, paywall | Free, server-side | Free, unlimited, client-side |
| Puzzles | Limited free, paywall | Free | Free (5 million) |
| Lessons | Paywall after basics | No structured lessons | 200 free interactive lessons |
| Profile reports | Paid "Insights" | Basic stats | Free deep analysis |
| Engine | Server-side | Server-side | Client-side (your device) |
| Cost | $99/year for full | Free | Free |
| Privacy | Account required | Account required | No account needed to start |

## Who is Lumichess for?

- Chess players rated 400-2200 who want to improve
- Players who want free, unlimited game analysis without a subscription
- Beginners who want structured lessons (not just puzzles)
- Players who use both Chess.com and Lichess and want unified stats
- Privacy-conscious players (all analysis runs locally)

## Technical Details

- Vanilla JavaScript, no framework (fast loading)
- Stockfish 17.1 NNUE running in Web Workers (WebAssembly)
- Works offline after first load (PWA)
- IndexedDB for local storage
- Total page weight: ~3 MB compressed for full exploration
- No ads, no tracking, no data collection

## Pages

- https://lumichess.com — Landing page
- https://lumichess.com/game-report — Game analysis and report
- https://lumichess.com/analysis — Interactive analysis board
- https://lumichess.com/puzzles — Puzzle hub (daily, training, storm)
- https://lumichess.com/learn — 200 chess lessons
- https://lumichess.com/play — Play against bots
- https://lumichess.com/database — Opening database and game library
- https://lumichess.com/monitor — Chess stats dashboard
- https://lumichess.com/profile-report — Profile analysis
- https://lumichess.com/insights — Performance insights