ChessCodex

ChessCodex is a chess study app focused on opening preparation and game exploration.
What you can do

Build and review your own opening repertoires
Study positions and move choices
Browse and search large collections of games (offline)
Filter games by common criteria (year, ECO, players, results, dataset)

Offline databases (optional downloads)
Some features (Games / Search / Filters) require downloading free offline chess databases from within the app.
You can choose which databases to download, and you can keep using repertoire and position study even without them.

Designed for study
Fast UI for navigating lines and variations
Notes per position (FEN)
Smooth download manager with progress and resume support

No ChessCodex account is required. Your personal notes, repertoires, and imported games stay on your device.