Chessstack is a chess repertoire builder and opening trainer. Build your repertoire move by move using master games, Lichess rating stats and Stockfish, then drill it with spaced repetition so you never forget a line. Practice your lines against a computer that plays like real opponents, prepare for specific opponents, and check your Lichess or Chess.com games against your prep. Free with one repertoire, or unlimited for $1/month or $10/year. Open source (AGPL) and self-hostable with Docker.
