ReplayChess is a free, open-source alternative to Chess.com and Lichess for people who want to play chess history rather than browse it. Where other sites give you a game database or a video, ReplayChess starts you at the critical position of a famous game and lets you play it out against a friend, a matched opponent, or Stockfish running in your browser.
50+ chess legends with playable famous positions. 3,600+ ECO-coded openings, each playable from the position. Real-time multiplayer with rating-based matchmaking and private challenge links. Post-game analysis: match rate vs the original moves, divergence detection, practice mode vs Stockfish. Installs as a PWA; MIT-licensed source on GitHub. Free to play; Player plan $4.99/month unlocks the full catalogue.