ChessReflex
A shipped SaaS I founded and built solo
Every opening trainer makes you replay whole lines start to finish. Almost all of that is wasted — you already know the first six moves. What you actually forget is the branch points, the positions where your opponent has a real choice and you need the right answer.
So ChessReflex inverts it: the trainer finds the decision points in a repertoire and drills those, cycling through an opponent's options with minimal board movement. The second half is personalization — it pulls your real games from Chess.com or Lichess, indexes every position you reached, runs a Stockfish pass to find your first blunder, and hands your own mistake back as a puzzle.
It's a real product, not a demo: subscription billing, auth, and a content library that's verified by an automated test suite rather than trusted.
What it does
- “Easy Memory” engine drills branch points instead of whole lines
- Mines your own Chess.com / Lichess games and finds the blunder with Stockfish
- Stripe subscriptions with a 7-day trial and webhook-driven Pro entitlements
- Supabase auth — email and Google OAuth
- FSRS spaced repetition for review scheduling
- 15 opening repertoires, 750 engine-verified lines, plus curated tactical traps
- Automated test suite checks legality, structure, and transposition consistency