ChessBlunders.org: Learn From Your Mistakes with Stockfish-Powered Analysis
Building a SaaS platform that imports your Chess.com games, analyzes every position with Stockfish 16, and creates personalized puzzles from your blunders.
The Problem with Generic Tactics Training
Every chess player makes blunders. The painful part is making the same blunders over and over again. Traditional tactics trainers serve random puzzles from a massive database, but they miss something crucial: the positions where you actually struggle are the ones from your own games, in your own openings, with your own typical mistakes.
ChessBlunders.org addresses this by analyzing your actual Chess.com games and extracting the exact positions where you went wrong. Instead of practicing generic tactics, you practice the specific patterns you need to improve.
How It Works
The platform connects to your Chess.com account and imports your game history. Each game is then analyzed position-by-position using Stockfish 16, one of the strongest chess engines in the world. When the engine detects a significant evaluation drop after your move, it flags that position as a blunder.
These blunders are converted into interactive puzzles. You see the position where you made the mistake, and your task is to find the best move. The system tracks your accuracy, shows you the top engine recommendations, and provides hints when you get stuck.
The Technical Architecture
The frontend is built with Next.js 15 and React 19, using TypeScript throughout for type safety. The dark-themed UI uses Tailwind CSS with a custom color palette optimized for chess board visualization. The interactive chess board is powered by react-chessboard with chess.js handling move validation.
Supabase handles authentication, database storage, and real-time subscriptions. The PostgreSQL database stores user profiles, imported games, analysis results, and detailed progress tracking for each puzzle attempt.
The engine analysis runs on a cloud-based Stockfish service built with Python FastAPI. Each position is evaluated with configurable depth settings, returning centipawn evaluations, mate scores, and the top alternative moves. The service supports batch processing for analyzing entire games efficiently.
Blunder Detection Algorithm
Not every mistake is worth practicing. The algorithm uses evaluation drop thresholds to identify meaningful blunders—positions where you had a good move available but played something significantly worse. Minor inaccuracies are filtered out to focus on the positions that really matter.
The system also excludes hopeless positions where the game was already lost. Practicing moves in positions where you were down a queen anyway is not productive training. The goal is to focus on positions where you had real chances but let them slip away.
Key Features
- Chess.com game import with automatic analysis
- Stockfish 16 engine evaluation for every position
- Interactive puzzle mode with move validation
- Detailed analytics: accuracy breakdown, streaks, solve times
- Blunder severity categorization (minor, medium, major)
- Hint system showing the best move
- Game-by-game analysis view with blunder highlights
- Progress tracking across practice sessions
The SaaS Model
ChessBlunders.org operates on a freemium model. Free users can analyze up to 100 games—enough to get started and see real value from the platform. Premium subscribers at $4.99/month get access to 1,000 analyzed games, unlimited retention, and higher analysis depth settings.
Stripe handles payment processing with secure subscription management. The pricing is designed to be accessible while covering the computational costs of running Stockfish analysis at scale.
Why This Approach Works
The most effective learning happens when you study your own mistakes. Research in chess improvement consistently shows that analyzing your own games is more valuable than solving random puzzles. ChessBlunders.org automates this process, turning the tedious work of game analysis into an engaging practice tool.
By focusing on positions from your actual games, you practice patterns that are relevant to how you play. You see your typical opening structures, your preferred piece placements, and the kinds of positions where you consistently go wrong. This targeted practice builds pattern recognition where you need it most.
Try It Yourself
ChessBlunders.org is live and ready to help you improve. Connect your Chess.com account, import your games, and start practicing the positions where you actually blundered. The free tier gives you plenty of room to see if the approach works for you.