architecture

Four folders with empty __init__.py files carry real contracts: layer boundaries, a unit of work per request, JWT tenant claims, and the 72-byte bcrypt gate.

TL;DR: Four seemingly empty folders establish layered contracts in a FastAPI skeleton, keeping business logic, technical details, and HTTP translation cleanly separated. A yield-based dependency handles transactions per request, committing only on success so multi-table use cases stay atomic. Multi-tenancy rides in JWT claims, bcrypt limits get enforced at the validation gate, and swappable signal sources await future needs.