Python Application Architecture

Modern Python application architecture following functional core / imperative shell pattern, Domain-Driven Design, and type-safe data modeling.

Core Principle: Functional Core / Imperative Shell

Separate pure business logic from side effects:

• Functional Core: Pure functions, business logic, no IO
• Imperative Shell: Coordinates external dependencies, handles side effects

See references/functional-core.md for detailed patterns and examples.

Layered Architecture

Follow bottom-up dependency flow: