Directory Structure
Understanding how Fastman organizes your code.
Feature Pattern (Default)
The feature pattern uses vertical slices—each feature contains everything it needs.
my-api/
├── app/
│ ├── core/ # Shared infrastructure
│ │ ├── __init__.py
│ │ ├── config.py # Settings from environment
│ │ ├── database.py # SQLAlchemy session
│ │ └── dependencies.py # FastAPI dependencies
│ │
│ ├── features/ # Feature modules
│ │ ├── user/
│ │ │ ├── __init__.py
│ │ │ ├── models.py # User SQLAlchemy model
│ │ │ ├── schemas.py # User Pydantic schemas
│ │ │ ├── service.py # User business logic
│ │ │ └── router.py # User API endpoints
│ │ │
│ │ └── post/
│ │ ├── models.py
│ │ ├── schemas.py
│ │ ├── service.py
│ │ └── router.py
│ │
│ └── main.py # App entry point
│
├── database/
│ ├── migrations/ # Alembic migrations
│ │ └── versions/
│ └── seeders/ # Database seeders
│
├── tests/
│ ├── factories/ # Model factories
│ └── test_*.py # Test files
│
├── .env # Default environment variables
├── .env.development # Development settings
├── .env.staging # Staging settings
├── .env.production # Production settings
├── alembic.ini # Migration config
└── pyproject.toml # Dependencies
API Pattern
The API pattern groups code by HTTP resource:
app/
├── api/
│ ├── v1/
│ │ ├── users.py
│ │ └── posts.py
│ └── v2/
├── models/
├── schemas/
└── services/
Layer Pattern
The layer pattern separates by technical concern:
app/
├── controllers/
├── models/
├── repositories/
├── schemas/
└── services/
Key Files
| File | Purpose |
|---|---|
app/main.py | Application factory, router mounting |
app/core/config.py | Pydantic settings, loads env file by ENVIRONMENT |
app/core/database.py | SQLAlchemy engine and session |
alembic.ini | Database migration configuration |
.env | Fallback environment variables (never commit!) |
.env.development | Development environment settings |
.env.staging | Staging environment settings |
.env.production | Production environment settings |