Why Clean Architecture Matters for Fast-Moving Startups

The Velocity Trap

Early-stage startups often treat architecture as an afterthought, prioritizing rapid feature shipping over code structure. However, without clear boundaries, codebases quickly devolve into tangled webs where every new feature risks breaking existing behavior.

The Vertical Slice Solution

Instead of horizontal layer dumping grounds, organizing code around vertical business slices allows teams to iterate on individual features independently.

src/modules/enquiries/
  ├── domain/        # Pure invariants
  ├── application/   # Use cases & ports
  ├── infrastructure/# Supabase adapters
  └── presentation/  # Server Actions & UI

Benefits in Practice

1. **High Testability**: Core rules are tested with fast in-memory unit tests.

2. **Low Cognitive Load**: Engineers working on an enquiry form only touch the `enquiries` module.

3. **Easy Refactoring**: Changing a database adapter requires zero changes to the UI layer.