Code Module Design

Design deep modules: a lot of behaviour behind a small interface, placed at a clean seam and tested through that interface. Use these terms and principles wherever code is designed or restructured, so callers get leverage, maintainers get locality, and tests cross the same seam callers do.

Glossary

Use these terms exactly; a shared vocabulary is the point. Reach for the listed term before "component," "service," "API," or "boundary."

Module: Anything with an interface and an implementation, at any scale: a function, class, package, or a slice spanning tiers. Avoid: unit, component, service