Scope-Appropriate Architecture

Right-size every architectural decision to the project's actual needs. Not every project needs hexagonal architecture, CQRS, or microservices.

Core principle: Detect the project tier first, then constrain all downstream pattern choices to that tier's complexity ceiling.

The 6 Project Tiers

Tier	LOC Ratio	Architecture	DB	Auth	Tests
1. Interview/Take-home	1.0-1.3x	Flat files, no layers	SQLite / JSON	None or basic	8-15 focused
2. Hackathon/Prototype	0.8-1.0x	Single file if possible	SQLite / in-memory	None	Zero
3. Startup/MVP	1.0-1.5x	MVC monolith	Managed Postgres	Clerk/Supabase Auth	Happy path + critical
4. Growth-stage	1.5-2.0x	Modular monolith	Postgres + Redis	Auth service	Unit + integration
5. Enterprise	2.0-3.0x	Hexagonal/DDD	Postgres + queues	OAuth2/SAML	Full pyramid
6. Open Source	1.2-1.8x	Minimal API surface	Configurable	Optional	Exhaustive public API