These architecture notes and diagrams show libscid from domain-centred angles. They are companions to the API reference: use them to understand ownership, conversion points and the shape of the public model before drilling into individual classes and functions.

Core is the chess model: games, positions, movetext, notation and PGN.

Database stores and queries game collections while materialising Core games on demand.

ECO classifies opening positions and provides the compact opening-code vocabulary.

Spelling is the name-authority layer for canonical database names and player metadata.