Chessdriller is an open-source app for spaced repetition training of chess openings. It's a free and libre alternative to the spaced-repetition features of Chessable, ChessTempo, Chessmadra, ChessHQ, Chess Position Trainer, Bookup, Listudy, etc.
To try Chessdriller out, just log in with Lichess to get started. A Lichess account is needed since your repertoire is stored as Lichess studies.
This is a fully functional beta version. You're very welcome to email me about any issues, feedback or suggestions, or just to chat about chess. Github issues are also welcome.
Cheers,
Tim